National Oceanic and Atmospheric Administration • NOAA’s National Ocean Service • Office of Response and Restoration

NAT OI NAL OCEANIC AND ATMOSPHERIC ADMINISTRAT OI N

U.S. DEPARTMENT OF COMMERCE

BIOLOGY, PLANNING, AND RESPONSE

Oil and 

Sea Turtles

August 2003

Gary Shigenaka, Technical Editor

Contributing Authors

Sarah Milton and Peter Lutz 

Florida Atlantic University

Gary Shigenaka, Rebecca Z. Hoff, Ruth A. Yender, and Alan J. Mearns

NOAA’s National Ocean Service/Offi ce of Response and Restoration/

Hazardous Materials Response Division

National Oceanic and Atmospheric Administration • NOAA’s National Ocean Service • Office of Response and Restoration

NAT OI NAL OCEANIC AND ATMOSPHERIC ADMINISTRAT OI N

U.S. DEPARTMENT OF COMMERCE

BIOLOGY, PLANNING, AND RESPONSE

Oil and 

Sea Turtles

Cover photograph courtesy of Ursula Keuper-Bennett

1

Table of Contents

Introduction

Chapters

Acknowledgments 5

Introduction 7

1 Sea Turtle Taxonomy and Distribution 9

 Key Points 9

 What Is a Sea Turtle? 9

 Sea Turtle Species and Their Geographic Distribution 10

 For Further Reading 19

2 Life History and Physiology 21

 Key Points 21

 Life History 21

 Physiology 23

 For Further Reading 24

3 Natural and Human Impacts on Turtles 27

 Key Points 27

 Natural Mortality Factors 27

 Anthropogenic Impacts 29

 For Further Reading 32

4 Oil Toxicity and Impacts on Sea Turtles 35

 Key Points 35

 Toxicity Basics 36

 Indirect Effects of Oil on Sea Turtles 43

 For Further Reading 45

5 Response Considerations for Sea Turtles 49

 Key Points 49

 Open-Water Response Options 50

 Shoreline Cleanup 57

 Indirect Response Impacts 59

 Preventative Measures 60

 Application of Sea Turtle Information for Spill Response and Planning 60
2

 For Further Reading 66

6 Case Studies of Spills that Threaten Sea Turtles 69

 Key Points 69

 Past and Present Spills that Threaten Sea Turtles 69

 Selected Case Studies 73

 Impacts of Tarballs 81

 Oil-Related Strandings 81

 The Future 82

 For Further Reading 83

Conclusions 85

Glossary of Terms and Abbreviations 87

Appendix A: Protocol for Recovery of Oiled Marine Turtles at Sea 89

Appendix B: Excerpted Sections from Marine Turtle Guidelines, State of Florida 

Fish and Wildlife Conservation Commission 90

Appendix C: Sea Turtle Stranding and Salvage Network (STSSN) Coordinators 109

Tables

Table 1.1 Status of turtle species found in U.S. waters 10

Table 1.2 Summary of adult habitat and diets for the six sea turtle species found 

in U.S. waters 11

Table 3.1. A summary of natural and anthropogenic impacts on sea turtles 32

Figures

Figure 1.1 Species identifi cation guide to sea turtles found in U.S. territorial waters 12

Figure 1.2 Male loggerhead turtle swimming in Argostoli harbor, Kefalonia, Greece 13

Figure 1.3 Green turtle 14

Figure 1.4 A leatherback turtle covers her nest in French Guiana 15

Figure 1.5 A Kemp’s ridley turtle 16

Figure 1.6 A hawksbill turtle 17

Figure 1.7 Hawksbill hatchlings emerge from a nest on Pajaros Beach, 

Isla de la Mona, in the Mona Channel west of Puerto Rico 17

Figure 1.8 An olive ridley turtle 18

Figure 1.9 Olive ridley turtles leave the beach at Ostional, Costa Rica 18
3

Figure 1.10 A fl atback turtle on Abutlion Island, Lownedal Island group, 

Western Australia 18

Figure 2.1 A loggerhead hatchling in sargassum 22

Figure 3.1 A green turtle with fi bropapilloma tumors at the base of its fl ippers 29

Figure 3.2 Trawl-caught sea turtles off Cape Canaveral, Florida 29

Figure 3.3 On a nesting beach in North Carolina homeowners placed sandbags to 

halt erosion, rendering previous turtle nesting sites inaccessible to 

sea turtles 30

Figure 3.4 A hawksbill turtle entangled in plastic line and fi shing net 31

Figure 3.5 This X-ray image of a juvenile green turtle shows fi shing hooks and 

other tackle in throat 32

Figure 4.1 A juvenile green turtle oiled during a spill in Tampa Bay, Florida, in 1993 36

Figure 4.2 Conceptual framework of sea turtle behavioral responses to oil exposure 41

Figure 4.3 Conceptual framework for the effects of oil exposure to sea turtles 41

Figure 5.1 Schematic of Section 7 endangered species consultation process 51

Figure 5.2 Conceptual framework for considering chemical dispersant effects to 

sea turtles 53

Figure 5.3 Decision fl owchart for evaluating in-situ burning as a spill response 

option 56

Figure 5.4 A sea turtle nest endangered by the 1993 Bouchard B155 oil spill in 

Tampa Bay 57

Figure 5.5 An Environmental Sensitivity Index map for Florida’s turtle habitat areas 61

Figure 5.6 Times when oil near or on nesting beaches will have the most and 

least effect on turtles, by species 62

Figure 5.7 An oiled green turtle recovered by the Israeli Sea Turtle Rescue Center 

in August 1999 65

Figure 6.1 Sources of oil spilled in tropical areas, 1992–2001 72

Figure 6.2 Types of oil and fuels spilled in tropical incidents, 1992–2001 72

Figure 6.3 Causes of incidents in tropical areas, 1992–2001 72

Figure 6.4 A nesting beach oiled after the 1993 Bouchard B155 spill in 

Tampa Bay, Florida 77

Figure 6.5 A juvenile green turtle oiled during the 1993 Bouchard B155 spill in 

Tampa Bay, Florida 77

Figure 6.6 Juvenile green turtle recovered during the Morris J. Berman barge spill 

in the waters off Culebra, Puerto Rico 79

5

Acknowledgments

Although there is a team of people who are identifi ed as co-authors of this document, many more need to be recognized as contributors. Without their help and (mostly) 

willing assistance, this effort would not have been possible.

Brad Benggio, Janos Csernoch, Dr. Matthew Godfrey, Chris Johnson, Ursula 

Keuper-Bennett, Dr. Anne Meylan, Celia Moorley-Bell, Kellie Pendoley, Dr. Pamela Plotkin, 

Michelle Schärer, Dr. Asaf Senol, Douglas Shea, Patricia Sposato, Michael White, Dr. Blair 

Witherington, and Dr. Jeanette Wyneken graciously contributed personal photographs of 

turtles and turtle habitat for inclusion in the report—as did the authors. The nicely illustrated identifi cation guide (page 10) was created by Dawn Witherington and Dr. Wyneken 

and is reproduced with their permission.

Patrick Opay of the Sea Turtle Team in the NOAA/National Marine Fisheries 

Service Offi ce of Protected Resources in Silver Spring, Maryland, and Sandra MacPherson, 

National Sea Turtle Coordinator for the U.S. Fish and Wildlife Service in Jacksonville, 

Florida, reviewed the protected species information for accuracy. Marydele Donnelly 

of the Ocean Conservancy in Washington, D.C., reviewed and updated the status of sea 

turtle conservation efforts worldwide. Jim Jeansonne of the NOAA Damage Assessment 

Center (St. Petersburg, Florida) provided detailed accounts of recent spills affecting sea 

turtles and their habitat. Dr. Karen Eckert (Wider Caribbean Sea Turtle Conservation 

Network, Beaufort, North Carolina) shared information gathered by her organization on 

oil spills affecting sea turtles in the Caribbean region. Dr. George Balazs (Marine Turtle 

Research Program, NOAA/National Marine Fisheries Service Honolulu Laboratory, Hawaii), 

Mr. Felix Lopez (U.S. Fish and Wildlife Service, Boqueron, Puerto Rico) Dr. Molly Lutcavage 

(New England Aquarium, Boston, Massachusetts), Dr. Anne Meylan (Florida Marine 

Research Institute, St. Petersburg, Florida), Dr. Jacqueline Michel (Research Planning Inc., 

Columbia, South Carolina), and Dr. Robert Pavia (NOAA/HAZMAT, Seattle, Washington) 

contributed valuable review comments, which improved the technical and overall quality 

of the product.

Brian Voss and Maureen Wood of the NOAA Seattle Regional Library sought out 

and found even the most obscure of the sea turtle references we requested, and thus 

were largely responsible for the foundation of information on which this document is 

built.

Andrea Jarvela helped blend a mish-mash of styles and content and made them 

both readable and engaging. Kristina Worthington re-drew our primitive graphics and 

was responsible for fi nal lay-out. Vicki Loe supervised the overall design and production 

for this series of documents.

Finally, funding for this book was provided through NOAA’s Coral Reef 

Conservation Program, which is designed to protect and restore the nation’s coral reefs 

and assist conservation of reef ecosystems internationally. This program includes efforts 

NMFS - National 

Marine Fisheries Service 

(NOAA).

NOAA - National 

Oceanic and 

Atmospheric 

Administration 

(U.S. Department of 

Commerce).
6

to monitor and assess coral health, map coral reef ecosystems, conduct research to better 

understand biological, social, and economic factors that effect coral reefs, partnerships 

to reduce the adverse affects of fi shing, coastal development, and pollution, and identify 

coral reef areas for special protection.

If I have omitted acknowledging the contributions of others, please forgive the 

oversight and understand that their efforts are nonetheless deeply appreciated.
7

Introduction

Few animals in the world’s oceans evoke the kind of wonder inspired by sea 

turtles. Ancient in their origins, sea turtles are bestowed with a mystical quality that in 

part derives from their longevity as inhabitants of the world’s oceans and in part from 

their uncanny ability to navigate over vast expanses of water to return to their natal 

beaches.

However, few animals are at greater risk from an 

unfortunate confl uence of global changes, widespread 

disease, and a host of problems of human origin. The 

latter category includes inevitable human population 

growth and the consequences of habitat destruction, 

impairment and entanglement in plastic trash, the persistent belief that turtle fl esh and turtle eggs confer nearly 

supernatural health benefi ts, the inherent beauty and 

rarity of turtle shell jewelry, and even the indirect impacts 

of the breakdown of indigenous social mores within the 

populations of far-fl ung islands where turtles also dwell. 

Among these many risks to the continued existence of 

turtles is that from oil spills.

Admittedly, in the spectrum of threats facing sea turtles, oil spills do not rank 

very high. They are generally rare events, affecting a limited geographic area. Oil is not 

the most toxic material that could be spilled in a sensitive marine environment, which in 

places include turtle habitat. Oil may even be released naturally from seeps and vents. 

Yet in 1979 a massive oil spill resulting from a drilling platform blowout in the Gulf of 

Mexico threatened one of the only known nesting beaches of a particularly threatened 

sea turtle, the Kemp’s ridley. The spill ultimately resulted in minor impacts to the Kemp’s 

ridley population, but a major tragedy was averted.

The 1979 Gulf of Mexico incident emphasized the tenuous nature of existence for 

threatened sea turtles in the world’s oceans, and how a single catastrophic oil spill might 

serve as the synergistic “tipping point” that could prove devastating to externally stressed 

populations.

Those of us who work on environmental issues related to oil and chemical spill 

response often think about our job in the context of game theory and “minimum regret.” 

We identify courses of action that do not eliminate risk, and in fact expand the area we 

consider at risk; but, ultimately, we minimize the regret we may feel about our course of 

action by explicitly considering the consequences of unlikely events. The probability of 

an incident affecting sea turtles may well be low—that is, mathematically negligible—

but the result of such a low-probability event occurring at just the wrong time of year 

and at the wrong location could be catastrophic and unacceptable for a given populaAn oiled green turtle recovered 

by the Israeli Sea Turtle Rescue 

Center in August 1999. This and 

one other turtle were cleaned, 

rehabilitated, and released about 

two months later. Photo courtesy 

of Yaniv Levy, Israeli Sea Turtle 

Rescue Center, Hofi t, Israel.
8

tion. Therefore, we plan for such an occurrence, while hoping we never need to invoke 

the plans we make.

The guidance document you hold is a part of that planning effort. It is the third 

in a series of publications prepared by NOAA’s Offi ce of Response and Restoration to 

provide response-relevant information on specifi c warm-water resources at risk. Previous 

publications include oil impacts to coral reef and mangrove ecosystems. Our intent is 

to present a basic overview of sea turtle biology, summarize what is known about the 

effects of oil on sea turtles, review potential response actions in the event of a release, and 

present case histories from previous spills that potentially could or actually have affected 

sea turtles. Our audience is intended to include spill responders and planners, resource 

managers, sea turtle rehabilitators, veterinarians—and anyone who is interested in the 

continued survival and health of one of the ocean’s most intriguing inhabitants.

 Gary Shigenaka, Technical Editor

 National Oceanic and Atmospheric Administration

 Offi ce of Response and Restoration

 Seattle, Washington

NOAA - 

National Oceanic 

and Atmospheric 

Administration. 

(U.S. Department of 

Commerce).

RAR - resources at risk.
9

Chapter 1 Sea Turtle Taxonomy and Distribution

Sarah Milton and Peter Lutz

Key Points

· Sea turtles are long-lived, slow to mature, air-breathing, diving marine reptiles that 

have terrestrial life stages, primarily nesting and egg development, and hatchlings.

· There are seven living species of sea turtles; fi ve are commonly found in continental 

U.S. waters: loggerhead, green, leatherback, hawksbill, and Kemp’s ridley turtles. The 

olive ridley turtle is found in U.S. territorial waters in the Pacifi c.

· All fi ve species found in coastal U.S. waters are listed as endangered or threatened 

under the Endangered Species Act; all species are on the Convention on 

International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix I 

list, which prohibits their traffi c in international trade.

· Sea turtle species are identifi ed by the numbers and pattern of plates (called scutes) 

on their shells and the scale pattern on their heads.

· While most sea turtles are tropical to subtropical, especially for nesting, some species 

range as far north as the waters off Newfoundland and Alaska and as far south as the 

coasts of Chile and Argentina.

What Is a Sea Turtle?

The modern sea turtle is a large (35 to 500 kilograms [kg]), long-lived, airbreathing reptile highly adapted and modifi ed for a marine lifestyle. While the most 

obvious adaptation is the fl attened, streamlined shell, or carapace (dorsal shell), sea 

turtles also have highly modifi ed limbs, with the forelimb bones, called phalanges, 

extended to thin, fl attened, oarlike fl ippers for swimming. The paddlelike forelimbs are 

relatively non-retractable, however, so they make the turtles awkward and vulnerable on 

land. Other adaptations to marine life include anatomical and physiological means of 

breathhold diving and excreting excess salt.

Although they are predominantly marine, sea turtles return to land to nest, and 

after the eggs develop and hatch, the hatchlings return directly to the sea. In some 

locations (Hawaii and Australia, for example), juveniles, subadults, and adults also come 

ashore to bask. In addition, sea turtles migrate great distances, traveling hundreds or 

even thousands of kilometers between foraging and nesting grounds, thus they are 

excellent navigators as well. Hatchlings orient in part by the earth’s magnetic fi elds, as do 

migrating adults.

Carapace - dorsal 

(top) shell of a turtle.

CITES - Convention on 

International Trade in 

Endangered Species of 

Wild Fauna and Flora.

Phalanges - 

long “fi nger” bones of a 

turtle fl ipper.

Scute - plates of the 

sea turtle shell.
10

Sea Turtle Species and Their Geographic Distribution

Five species of sea turtles—loggerhead, green, leatherback, Kemp’s ridley, and 

hawksbill—are commonly found in U.S. coastal waters. A sixth, the olive ridley, is found 

in U.S. territorial waters. All fi ve species are listed as endangered or threatened under the 

U.S. Endangered Species Act. Spill response personnel should be aware that only trained 

and authorized personnel designated under a federal Endangered Species Act permit or 

cooperative agreement can be involved in handling sea turtles and their nests. Table 1.1 

summarizes the current status of sea turtle species under the act, as well as critical habitat 

areas: Table 1.2 summarizes their habitats and diets.

Table 1.1 Status of turtle species found in U.S. waters. 

Common and 

Species Names Status in the United States

Date of 

Listing Critical habitat

Loggerhead

Caretta caretta

Threatened throughout its 

range.

7/28/78 None designated in the United States.

Green

Chelonia mydas

Breeding colony populations 

in Florida and on the Pacific 

coast of Mexico are listed as 

endangered; all others are 

listed as threatened.

7/28/78 50 CFR 226.208 Culebra Island, Puerto Rico – Waters 

surrounding the island of Culebra from the mean high 

water line seaward to 3 nautical miles (5.6 km). These 

waters include Culebra’s outlying Keys including Cayo 

Norte, Cayo Ballena, Cayos Geniquí, Isla Culebrita, 

Arrecife Culebrita, Cayo de Luis Peña, Las Hermanas, El 

Mono, Cayo Lobo, Cayo Lobito, Cayo Botijuela, Alcarraza, 

Los Gemelos, and Piedra Steven.

Leatherback

Dermochelys coriacea

Endangered throughout its 

range.

6/2/70 50 CFR 17.95 U.S. Virgin Islands – A strip of land 0.2 

miles wide (from mean high tide inland) at Sandy Point 

Beach on the western end of the island of St. Croix 

beginning at the southwest cape to the south and running 1.2 miles northwest and then northeast along the 

western and northern shoreline, and from the southwest cape 0.7 miles east along the southern shoreline.

50 CFR 226.207 The waters adjacent to Sandy Point, 

St. Croix, U.S. Virgin Islands, up to and inclusive of the 

waters from the hundred fathom curve shoreward 

to the level of mean high tide with boundaries at 

17°42’12” North and 64°50’00” West.

Kemp’s ridley

Lepidochelys kempii

Endangered throughout its 

range.

12/2/70 None designated in the United States.

Threatened - 

any species likely to 

become endangered in 

the foreseeable future 

(from the Endangered 

Species Act of 1973).

Endangered - 

Any species of animal 

or plant that is in 

danger of extinction 

throughout all or a 

signifi cant part of 

its range (from the 

Endangered Species 

Act of 1973).
11

Table 1.1 Cont.

Common and 

Species Names Status in the United States

Date of 

Listing Critical habitat

Hawksbill

Eretmochelys imbricata

Endangered throughout its 

range.

6/2/70 50 CFR 17.95 Puerto Rico: (1) Isla Mona. All areas of 

beachfront on the west, south, and east sides of the 

island from mean high tide inland to a point 150 m 

from shore. This includes all 7.2 km of beaches on 

Isla Mona. (2) Culebra Island. The following areas of 

beachfront on the north shore of the island from mean 

high tide to a point 150 m from shore: Playa Resaca, 

Playa Brava, and Playa Larga. (3) Cayo Norte. South 

beach, from mean high tide inland to a point 150 m 

from shore. (4) Island Culebrita. All beachfront areas 

on the southwest facing shore, east facing shore, and 

northwest facing shore of the island from mean high 

tide inland to a point 150 m from shore.

50 CFR 226.209 Mona and Monito Islands, Puerto Rico 

– Waters surrounding the islands of Mona and Monito, 

from the mean high water line seaward to 3 nautical 

miles (5.6 km).

Olive ridley

Lepidochelys olivacea

Breeding colony populations on the Pacific coast of 

Mexico are listed as endangered; all others are listed as 

threatened

7/28/78 None designated in the United States.

Source: http://northfl orida.fws.gov/SeaTurtles/turtle-facts-index.htm, Code of Federal Regulations.

Table 1.2 Summary of adult habitat and diets for the six sea turtle species found in U.S. waters.

Species Habitat Diet

Loggerhead Shallow continental shelf, coastal bays Benthic invertebrates—mollusks and crustaceans

Green Nearshore, coastal bays Herbivorous—seagrasses and macroalgae

Leatherback Pelagic Jellyfish

Kemp’s ridley Coastal bays, shallow continental shelf Fish and benthic invertebrates—crustaceans, squid, sea 

urchins

Hawksbill Reefs, coastal areas, lagoons Primarily sponges, also shrimp, squid, anemones

Olive ridley Coastal bays, shallow continental shelf Fish and benthic invertebrates—crustaceans, squid, sea 

urchins
12

All sea turtle species are on the Convention on International Trade in Endangered 

Species of Wild Fauna and Flora (CITES) Appendix I list, which prohibits their traffi c in 

international trade. In addition to coloring, range, and size, sea turtle species are positively identifi ed by the number and pattern of carapace scutes (plates of the shell) and 

scales on the head (Figure 1.1).

Figure 1.1 Species identifi cation 

guide to sea turtles found in U.S. 

territorial waters. Prefrontal 

scales are those located between 

the eyes. Lateral scutes lie on 

each side of the vertebral (center) 

scutes. Drawing courtesy of 

Dawn Witherington and Jeanette 

Wyneken. 
13

Loggerhead Turtle, Caretta caretta

The loggerhead turtle (Figure 1.2) is the most common nesting 

turtle found in coastal U.S. waters, where it is listed as threatened under the 

Endangered Species Act. The southeastern coast of the United States hosts 

the second largest breeding aggregate of loggerhead turtles in the world, 

30 percent of the world’s breeding population (the largest breeding population is in Oman). Ninety percent of U.S. nesting occurs along the central and 

southeast Florida coast, though regular nesting also occurs in Georgia, the 

Carolinas, and Florida’s Gulf coast.

Identification

Adults and subadults have reddish-brown carapaces and dull brown to yellowish 

bottom shells, called plastrons. Juveniles are also reddish brown, while hatchlings have a 

yellowish margin on the carapace and fl ippers. Loggerhead turtles have more than one 

pair of prefrontal scales (between the eyes) and fi ve lateral scutes on the carapace (Figure 

1.2). Hatchlings and juveniles have sharp keels on the vertebral scutes, which recede with 

age. Adults in the southeastern United State are approximately 92 centimeters (cm) in 

straight carapace length (SCL), with a mean mass of 113 kg; adults elsewhere are generally somewhat smaller. 

Range

Loggerheads range along the east coast of the United States, in the Gulf of 

Mexico, off southern Brazil, in the northern and southwestern Indian Ocean, near eastern 

Australia, in Japan, and in the Mediterranean. In the Western Hemisphere, loggerheads 

may range as far north as Newfoundland (rare) to as far south as Argentina. Along the 

Pacifi c coast, loggerheads range from the Gulf of Alaska southward, but are most frequently seen off the western Baja Peninsula. Nesting occurs in the northern and southern temperate zones and subtropics (they generally avoid nesting on tropical beaches).

Habitat

Adult and subadult loggerhead turtles are found primarily in subtropical (occasionally tropical) waters along the continental shelves and estuaries of the Atlantic, 

Pacifi c, and Indian Oceans. They are a nearshore species, but may be found in a variety 

of habitats from turbid, muddy-bottomed bays and bayous to sandy bottom habitats, 

reefs, and shoals. Juveniles swim directly offshore after hatching and eventually associate with the sargassum and pelagic drift lines of convergence zones. Juveniles from the 

southeastern United States may circumnavigate the entire northern Atlantic gyre before 

moving to nearshore habitats, when they have grown to 40 to 50 cm SCL.

Plastron - ventral 

(bottom) shell of a 

turtle.

SCL - straight carapace 

length.

Figure 1.2 Male loggerhead turtle 

swimming in Argostoli harbor, 

Kefalonia, Greece. Photo courtesy 

of Michael White.

Sargassum - 

genus of brown algae, 

also known as gulfweed. 

There are 15 species 

in the genus, and each 

has air bladders. Some 

species are free fl oating. 

Off the U.S. coast, south 

of Bermuda, is the 

Sargasso Sea, a large 

(two-thirds the size 

of the United States), 

loosely-defi ned portion 

of the Atlantic Ocean 

where an estimated 

7 million tons of live 

sargassum may be 

found.
14

Diet

Adults and subadults feed primarily on benthic mollusks and crustaceans. 

Hatchlings and juveniles consume coelenterates and cephalopod mollusks associated 

with pelagic drift lines.

Green Turtle, Chelonia mydas

The green turtle (Figure 1.3) is the largest hard-shelled sea turtle (cheloniid), and 

the second most common nesting turtle, in U.S. waters. While considered threatened in 

most parts of the world, the breeding populations in Florida and on Mexico’s Pacifi c coast 

are considered endangered.

Identification

The adult green turtle has a black to gray to greenish or 

brown carapace, often with streaks or spots, and a yellowish-white 

plastron. Hatchlings have a dark brown to black carapace and white 

plastron, with a white margin along the carapace and rear edges. 

Greens have one pair of prefrontal scales, four lateral scutes, a small 

rounded head, and a single visible claw on each fl ipper. Worldwide, 

green turtles vary in size and weight among different populations. In 

Florida, green turtles average 101 to 102 cm in carapace length (SCL) 

and weigh about 136 kg. 

Range

Adult green turtles, rare in temperate waters, are found in tropical and subtropical 

waters worldwide. In the United States they range from Texas to the U.S. Virgin Islands, 

near Puerto Rico, and north to Massachusetts. Major nesting areas are located in Costa 

Rica, Australia, Ascension Island, and Surinam. In the United States, small numbers nest 

in Florida, the U.S. Virgin Islands, and Hawaii. Culebra Island, Puerto Rico, is an important 

foraging area for juveniles.

A subspecies (possibly a distinct species), the black turtle (Chelonia agassizii) is 

confi ned to the eastern Pacifi c, with important nesting grounds in Mexico. The black 

turtle ranges from southern Alaska to southern Chile, but is usually found between Baja 

California and Peru.

Habitat

Like other sea turtle species, green turtles use three distinct habitats: nesting 

beaches, convergence zones in the open sea (hatchlings/juveniles), and benthic foraging 

grounds (adults/subadults). Juveniles move into benthic feeding grounds in relatively 

shallow, protected waters when they reach about 20 to 25 cm SCL. Foraging areas consist 

primarily of seagrass and algae beds, though they are also found over coral and worm 

Cheloniid -

hard-shelled sea 

turtles composed of 

the genera Chelonia, 

Caretta, Lepidochelys, 

Eretmochelys, and 

Natator; contrast to 

dermochelyid.

Figure 1.3 Green turtle. Photo 

courtesy of Douglas Shea.
15

reefs and rocky bottoms. In the United States, important foraging areas include Florida 

estuaries, such as Indian River Lagoon, and the French Frigate Shoals in Hawaii. Green 

turtles prefer nesting on high-energy beaches, often on islands.

Diet

Post-hatchling, pelagic-stage green turtles are believed to be omnivorous. Adults 

and subadults feed primarily on seagrasses and kelp.

Leatherback turtle, Dermochelys coriacea

The leatherback turtle (Figure 1.4), the largest and most pelagic sea turtle, is easily 

identifi ed by its lack of scutes (hence the name). The leatherback is listed as endangered.

Identification

This large sea turtle has seven ridges running from front to rear along its back 

instead of the usual scutes, with a continuous thin, black layer of skin, often with white 

spots. Leatherbacks have no scales on their heads and no claws on their fl ippers. They 

range in size from 150 to 170 cm SCL, and may grow to 500 kg (rarely, even to 900 kg). 

Hatchlings also have carapace ridges and lack scutes; they are two to three times larger 

than other sea turtle hatchlings.

Range

Adult leatherbacks may range as far north as the coastal waters off 

Newfoundland or the Gulf of Alaska: this is the species most frequently found 

stranded on beaches of northern California. Nesting is entirely tropical, 

however, occurring in Mexico, the eastern Pacifi c, Guyana, the South Pacifi c 

(Malaysia), coastal Africa, and the Caribbean (Costa Rica, Surinam, French 

Guiana, and Trinidad). Very small numbers (20 to 30) nest along the Florida 

coast each year, with larger numbers nesting in the U.S. Virgin Islands (St. Croix 

in particular) and Puerto Rico (mainland and Culebra Island). 

Habitat

Leatherbacks are primarily pelagic, deep-diving animals. They are occasionally 

seen in coastal waters, more frequently when nesting.

Diet

Leatherbacks primarily eat jellyfi sh and other coelenterates that inhabit the water 

column in the open ocean and pelagic colonial tunicates (pyrosomas).

Dermochelyid - 

leathery-shelled sea 

turtles (i.e., leatherback).

Figure 1.4 A leatherback turtle 

covers her nest in French 

Guiana. Photo courtesy of 

Matthew Godfrey.

Pyrosoma - 

pelagic colonial 

tunicate; most species 

inhabit tropical waters, 

with some up to 4 m in 

length.
16

 Kemp’s Ridley Turtle, Lepidochelys kempii

The Kemp’s ridley (Figure 1.5), along with the olive ridley, is the smallest of all sea 

turtles. Listed as an endangered species, this is the rarest sea turtle in the world, and it has 

the most restricted range of all U.S. sea turtle species. 

Identification

The small adult Kemp’s ridley sea turtle has a light gray to olive or gray-green 

carapace and a creamy white or yellowish plastron. Hatchlings are gray-black on both 

carapace and plastron. Kemp’s ridleys have more than one pair of prefrontal scales 

and fi ve lateral scutes. Adults usually weigh less than 45 kg, with an SCL averaging 65 

cm (nesting females range from 52 to 75 cm), and they are almost as wide as they are 

long.

Range

Except for the Australian fl atback turtle, the Kemp’s ridley has the most restricted 

range of all sea turtles, occurring primarily in the coastal areas of the Gulf of Mexico and 

the northwestern Atlantic Ocean. The primary nesting beach is near Rancho Nuevo, on 

Mexico’s northeast coast. While adults are confi ned almost exclusively to the Gulf of 

Mexico, the northeastern coast of the United States appears to be an important habitat 

for juveniles, which are often found in waters off New York and New England.

Habitat

As with other sea turtles, little is known of the Kemp’s ridleys’ post-hatchling, 

planktonic life stage. Young animals presumably feed on sargassum and associated 

infauna in the Gulf of Mexico. As juveniles, they frequent bays, coastal lagoons, and river 

mouths, then as adults move into crab-rich areas of the Gulf of Mexico over sandy or 

muddy bottoms.

Diet

Juvenile and adult Kemp’s ridleys are primarily crab-eaters. They also consume 

fi sh and a variety of invertebrates such as sea urchins and squid.

Figure 1.5 A Kemp’s ridley turtle. 

Photo courtesy of Dr. Jeanette 

Wyneken, Florida Atlantic 

University.
17

Hawksbill Turtle, Eretmochelys imbricata

The hawksbill turtle (Figure 1.6) is the most tropical sea turtle, and it is one of the 

most heavily poached, both as juveniles and adults, to obtain “tortoiseshell.” Hawksbills 

are endangered throughout their range.

Identification

The hawksbill turtle has thick carapace scutes, with streaks of brown and 

black on an amber background. The rear edge of the carapace is deeply serrated. 

Hawksbills have two pairs of prefrontal scales and four overlapping lateral scutes; a 

small, narrow head that tapers to a distinct hooked beak; and two claws on the front 

of its fl ippers. The second smallest sea turtle, nesting females vary in size from 27 to 

86 kg, with an SCL of 53 to 114 cm (the average is 95 cm).

Range

Hawksbills are found throughout the tropical oceans, with larger populations 

in Malaysia, Australia, the Western Atlantic from Brazil to South Florida, throughout the 

Caribbean, and in the southwestern Gulf of Mexico. In U.S. waters, hawksbills are found in 

the U.S. Virgin Islands (nesting beaches are in Buck Island National Monument, St. Croix), 

Puerto Rico (nesting beaches are on Mona Island, Figure 1.7), South Florida, along the 

Pacifi c coast from southern California southward, and in Hawaii.

Habitat

Hawksbills forage near rock or reef habitats in clear, shallow tropical waters. They are most common near a variety of reefs, from vertical 

underwater cliffs to gorgonian (soft coral) fl ats, and are found over seagrass or algae meadows. Adults are not usually found in waters less than 

20 m deep, while juveniles rarely leave shallow coral reefs. Pelagic-stage 

hawksbills presumably are associated with sargassum rafts, moving into 

shallow reefs when they reach 15 to 25 cm SCL, then into deeper waters 

as their size and diving capabilities increase.

Diet

Hawksbill turtles feed primarily on sponges (in the Caribbean, on only a few 

distinct species), but may also forage on corals, tunicates, and algae.

Figure 1.7 Hawksbill hatchlings 

emerge from a nest on Pajaros 

Beach, Isla de la Mona, in the 

Mona Channel west of Puerto 

Rico. Photo courtesty of Michelle 

Schärer, Department of Marine 

Sciences, University of Puerto 

Rico-RUM.

Figure 1.6 A hawksbill turtle. 

Photo of “Ake” courtesy of Ursula 

Keuper-Bennett.
18

Olive Ridley Turtle, Lepidochelys olivacea

The olive ridley (Figure 1.8), while probably the most numerous sea turtle 

worldwide, is rare in U.S. waters.

Identification

The olive ridley, like its close relative the Kemp’s ridley, is a small turtle. The 

adult carapace is dark gray and nearly round; hatchlings are gray-brown. Olive ridleys 

have two claws on each limb, more than one pair of prefrontal scales, and six or more 

lateral scutes.

Range

The olive ridley is found in Pacifi c and South Atlantic waters, but may 

occasionally be found in the tropical North Atlantic. Along the Pacifi c coast, 

the olive ridley ranges from the Gulf of Alaska to Central America, but is most 

common in the southern portion of this range. Enormous nesting aggregations, 

called arribadas, occur at two sites on Costa Rica’s Pacifi c coast (Figure 1.9), one 

site on Mexico’s Pacifi c coast, and two or three in northeastern India. Smaller 

nesting sites are found in Nicaragua and scattered along other tropical mainland 

shores.

Habitat

Olive ridleys are associated with relatively deep, soft-bottomed habitats inhabited 

by crabs and other crustaceans. They are common in pelagic habitats but also feed in 

shallower benthic habitats, sometimes near estuaries.

Diet

Carnivorous to omnivorous, olive ridley stomach contents have included crabs, 

mollusks, gastropods, fi sh, fi sh eggs, and algae.

Flatback Turtle, Natator depressus

The fl atback turtle (Figure 1.10) is confi ned to the waters along the northeast 

to northwest coast of Australia. The adult carapace is a dull olive-gray edged with pale 

brownish-yellow, and the plastron is creamy white. The fl atback inhabits inshore turbid 

waters in coastal areas along the main coral reefs and continental islands, where it feeds 

on a varied diet that includes algae, squid, invertebrates, and mollusks.

Figure 1.8 An olive ridley turtle. 

Photo courtesy of Janos Csernoch, 

Programa Restauración de 

Tortugas Marinas, Costa Rica

Figure 1.9 Olive ridley turtles 

leave the beach at Ostional, 

Costa Rica. Photo courtesy of 

Janos Csernoch, Programa 

Restauración de Tortugas 

Marinas, Costa Rica.

Figure 1.10 A fl atback turtle 

on Abutlion Island, Lownedal 

Island group, Western Australia. 

Photo courtesy of Kellie Pendoley, 

Murdoch University, Australia.

Arribada - mass 

nesting aggregation; 

Spanish, meaning 

literally, “arrived.”
19

For Further Reading

Bjorndal, K. A. 1982. Biology and Conservation of Sea Turtles, Smithsonian Institution Press, Washington, D.C.

Gulf of the Farallones National Marine Sanctuary. 1994. Beached Marine Birds and Mammals of the North 

American West Coast, NOAA Sanctuaries and Reserves Division, U.S. Dept. of Commerce, 1443-CX-8140-93-

011, 1994.

Lutz, P. L., and J. A. Musick, eds. 1997. The Biology of Sea Turtles, Vol. I. CRC Press, Boca Raton, Fla.

Lutz, P. L., J. A. Musick, and J. Wyneken, eds. 2002. The Biology of Sea Turtles, Vol. II. CRC Press, Boca Raton, Fla.

National Research Council. 1990. Decline of the Sea Turtles, National Academy Press, Washington, D.C.

Pritchard, P. C. H. 1997. Evolution, phylogeny, and current status. In: The Biology of Sea Turtles, Vol. I, P. L. Lutz and 

J. A. Musick, eds. CRC Press, Boca Raton, Fla. pp. 1–28

Pritchard, P. C. H. 1982. Nesting of the leatherback turtle Dermochelys coriacea in Pacifi c Mexico, with a new 

estimate of world population status. Copeia 3: 741.

Wyneken, J. 2002. The anatomy of sea turtles. NOAA Tech. Memo. NMFS-SEFSC-470, Miami, Fla.

21

Chapter 2 Life History and Physiology

Sarah Milton and Peter Lutz

Key Points

· The life history of all sea turtle species is similar; they are almost entirely marine.

· Females return to the beaches primarily to nest, emerging at night to dig an egg 

chamber and lay eggs. No further parental care is provided.

· Hatchlings of most sea turtles live for several years in the open ocean gyres, returning 

as juveniles to nearshore habitats.

· Some turtles migrate great distances between feeding and nesting areas.

· Sea turtles routinely dive for long periods. They have anatomical and physiological 

adaptations that permit a rapid exchange of air at the surface and the ability to carry 

oxygen “on board” for diving.

· Sea turtles excrete excess salt loads through modifi ed tear, or lachrymal, glands 

located behind the eyes.

Life History

The life history of all sea turtle species is similar. Mature, breeding females 

migrate from foraging grounds to nesting beaches, which may be nearby (tropical 

hawksbill, for example) or a signifi cant distance away (one population of green turtles 

migrates some 2,000 kilometers (km) from feeding grounds off Brazil to nesting beaches 

on Ascension Island in the mid-Atlantic). The turtles mate some time during the migration, usually in the spring, when mature males and females congregate off nesting 

beaches.

Female turtles must return to land to nest, generally crawling up a dark beach 

to above the high-tide line at night, although female Kemp’s ridley turtles nest predominantly during the day, as do olive ridleys, which nest in a large mass, or arribada. The 

general requirements for a nesting beach are that it is high enough to not be inundated 

at high tide, has a substrate that permits oxygen and carbon dioxide to diffuse into and 

out of the nest, and is moist and fi ne enough that it won’t collapse during excavation. 

The female uses her front fl ippers to toss loose surface sand aside to excavate a large 

body pit, then uses her hind fl ippers as “scoops” to dig a fl ask-shaped egg chamber, into 

which she deposits approximately 100 parchment-shelled eggs, about the size of PingPong balls (larger for leatherbacks). Once the eggs are deposited, she covers the eggs 

with moist sand and again uses her fl ippers to broadcast sand around the nesting area 

to disguise the exact location of the egg chamber. She then returns to the sea, providing 

Lachrymal gland - 

tear glands highly 

modifi ed to excrete 

excess salt.
22

no further parental care. Photographs of sea turtle nests and the typical tracks left by 

different turtle species are in Appendix B.

Females generally deposit from 1 to 10 egg clutches per season, laying at regularly spaced intervals of 10 to 20 days. Most turtle species nest only every two to four 

years. The exceptions to this general schedule are the Kemp’s and olive ridley turtles, 

which commonly nest each year, with no intervening nonbreeding seasons, unlike other 

turtle species. Both ridleys nest in arribadas, at three- to four-week intervals. Individual 

olive ridleys may nest one, two, or three times per season, typically producing 100 to 110 

eggs each time.

After an incubation period of about two months, hatchlings of all species dig their 

way up to the surface all together. Thus the majority of hatchlings emerge from the nest 

on a single night in a group numbering between 20 and 120, with only a few stragglers 

hatching on successive nights. High surface-sand temperatures can inhibit hatchling 

movement, so most emergences occur at night, after the sand has cooled, although 

daytime emergences on cloudy days or after a rain are not uncommon.

Upon emerging from the nest, the hatchlings scramble across the beach to the 

ocean, orienting away from the darkness of the duneline and moving toward the shine 

of the surf. Once in the water, hatchlings then orient into the waves, engaging in frenzied 

swimming that transports them to offshore waters within the fi rst 24 to 48 hours. There 

they will spend the next several years, feeding in sargassum beds, upwellings, and convergence zones of the open sea (Figure 2.1).

Sea turtles spend their early years caught up in the open ocean gyres. Thus 

turtles born on the U.S. Atlantic coast circle past Europe and the Mediterranean Sea 

before returning as juveniles to the U.S. eastern seaboard. Young turtles found off the 

California coast generally originate from beaches of the western Pacifi c.

As juveniles, most species enter the coastal zone, moving into bays 

and estuaries, where they spend more years feeding and growing to maturity. 

Estimates of age at sexual maturity vary not only among species, but also 

among different populations of the same species: as early as three years in 

hawksbills, 12 to 30 years in loggerheads, and 20 to 50 years in green turtles. 

Mature sea turtles then join the adult populations in the nesting and foraging 

grounds.

Leatherbacks are the exception to this life-history pattern. Upon hatching, leatherbacks do not move passively with the open ocean gyres; instead they become 

active foragers in convergence zones and upwellings. Leatherbacks are the most pelagic 

of the sea turtle species; they remain in deeper waters as both juveniles and adults, 

bypassing the nearshore stage common to other marine turtle species.

Figure 2.1 A loggerhead hatchling 

in sargassum. Photo courtesy of 

Dr. Blair Witherington, Florida 

Fish and Wildlife Conservation 

Commission.
23

Physiology

Sea turtles exhibit a number of adaptations as air-breathing, marine reptiles. 

Besides the obvious physical adaptations—the fl attened, streamlined carapace and 

elongated, paddlelike fl ippers (due to the space constraints of streamlining, neither head 

nor fl ippers are retractable)—the most important physical and physiological adaptations 

to the marine lifestyle are those that permit diving and excretion of excess salt. These 

adaptations are the focus of this section because they are the features that put sea turtles 

at particular risk when exposed to oil spills (discussed in Chapter 4).

Diving

Sea turtles are among the longest and deepest diving air-breathing vertebrates, 

spending as little as 3 to 6 percent of their time at the surface. While most sea turtle 

species routinely dive no deeper than 10 to 50 meters (m), the deepest recorded dives for 

leatherbacks are over 1,000 m! Routine dives may last anywhere from 15 to 20 minutes 

to nearly an hour. The primary adaptations that permit extended, repeated dives are 

effi cient transport of oxygen and a tolerance for low-oxygen conditions, or hypoxia. As 

surface breathers but deep divers, all the oxygen required by a diving turtle must be 

carried “on board.” Upon surfacing, a sea turtle exhales forcefully and rapidly, requiring 

only a few breaths, each less than 2 to 3 seconds, to empty and refi ll its lungs. Such high 

fl ow rates are possible because turtles have large, reinforced airways, and their lungs are 

extensively subdivided, which increases gas exchange between the them and the bloodstream. The blood will continue to pick up oxygen from the lungs even as oxygen stores 

are depleted to almost undetectable levels, stripping oxygen from the lungs to be used 

by the heart, brain, and muscles.

Unlike diving marine mammals, which have dark, iron-rich blood and muscle 

tissue that can store large amounts of oxygen, most sea turtles use the lungs as the 

primary oxygen store. (An exception to this is the leatherback, which is more like marine 

mammals in its ability to store oxygen in blood and tissues.) During routine dives, sea 

turtles will surface to breathe before they run out of oxygen, though when forced to 

remain submerged (for example, when caught in a trawl) their oxygen stores are rapidly 

consumed and instead they must convert glucose to lactic acid for energy, a process 

called anaerobic metabolism. Sea turtles can tolerate up to several hours without oxygen 

(due to their low metabolic rates and adaptations of the brain to survive without oxygen), 

but when they are forced to submerge, and thus expend much energy escaping, their 

survival time under water is greatly decreased. Lactic acid levels can rise rapidly, even to 

lethal levels. Turtles affected by sublethal levels of lactic acid may require up to 20 hours 

to recover, during which time they are vulnerable to capture or other stresses. Accidental 
24

drowning in shrimp trawls, drift nets, and long-line fi sheries is a major cause of sea turtle 

mortality worldwide.

Salt Excretion

A second important adaptation for a marine lifestyle is a way to excrete excess 

salt from seawater and food. Sea turtles, like all vertebrates, have a salt concentration in 

their body fl uids only about one-third that of seawater. Marine grasses and invertebrates 

(such as crabs and sea urchins), however, have the same salt levels as seawater. The 

turtle must excrete the excess salt consumed eating these plants and animals, because 

high salt levels in vertebrates interfere with a variety of bodily functions and can be 

lethal. To lessen the possibility of accidentally ingesting salt water while feeding, a sea 

turtle’s esophagus is lined with long, densely packed conical spines, or papillae, which 

are oriented downward, toward the stomach. Biologists believe that this defense against 

“incidental drinking” traps food, while contractions of the esophagus expel seawater out 

the mouth or nostrils, called nares. However, even with these features, most sea turtles 

still ingest high amounts of salt from their prey. Their kidneys are not powerful enough 

to excrete large salt loads, but highly modifi ed tear glands behind their eyes, when 

stimulated by high salt levels in the blood, can excrete a salt solution that is nearly twice 

as concentrated as seawater. The practical effect is that ingesting 1 liter of seawater will 

result in the excretion of 500 milliliters (ml) of tears, providing a net gain of 500 ml of 

salt-free water.

For Further Reading

Ackerman, R. A. 1977. The respiratory gas exchange of sea turtle nests (Chelonia, Caretta), Respir. Physiol. 31: 

19–38.

Ackerman, R. A. 1997. The nest environment and the embryonic development of sea turtles. In: The Biology of 

Sea Turtles, Vol. I, P. L. Lutz and J. A. Musick, eds. CRC Press, Boca Raton, Fla. 432 p.

Bjorndal, K. A. 1997. Foraging ecology and nutrition of sea turtles. In: The Biology of Sea Turtles, Vol. I, P. L. Lutz 

and J. A. Musick, eds. CRC Press, Boca Raton, Fla. pp. 199–231.

Crowder, L. B., S. R. Hopkins-Murphy, and J. A. Royle. 1995. Effect of turtle excluder devices (TEDS) on loggerhead sea turtle strandings with implications for conservation. Copeia 1995: 773.

Eckert, S. A. 2000. Global distribution of juvenile leatherback sea turtles. Hubbs Sea World Research Institute 

San Diego, Calif. pp. 99–294

Eckert, S. A., K. L. Eckert, P. Ponganis, and G. L. Kooyman. 1989. Diving and foraging behavior of leatherback sea 

turtles (Dermochelys coriacea). Can. J. Zool. 67: 2834.

Ehrhart, L. M. 1982. A review of sea turtle reproduction. In: Biology and Conservation of Sea Turtles, K. Bjorndal, 

ed. Smithsonian Institution Press, Washington, D.C. p. 29.

Hendrickson, J. R. 1982. Nesting behavior of sea turtles with emphasis on physical and behavior determinants 

of nesting success or failure. In: Biology and Conservation of Sea Turtles, K. Bjorndal, ed. Smithsonian Institution 

Press, Washington, D.C. p. 53.

Nares - external 

nostrils.
25

Jackson, D. C. 2000. Living without oxygen: Lessons from the freshwater turtle. Comp. Biochem. Physiol. A Mol. 

Integr. Physiol. 125(3): 299–315.

Lohmann, K. J., B. E. Witherington, C. M. Lohmann, and M. Salmon. 1997. Orientation, navigation, and natal 

beach homing in sea turtles. In: The Biology of Sea Turtles, Vol. I, P. L. Lutz and J. A. Musick, eds. CRC Press, Boca 

Raton, Fla. pp. 109–135.

Lutcavage, M., and P. L. Lutz. 1997. Diving physiology. In: The Biology of Sea Turtles, Vol. I, P. L. Lutz and J. A. 

Musick, eds. CRC Press, Boca Raton, Fla. pp. 277–296.

Lutcavage, M., and P. L. Lutz. 1991. Voluntary diving metabolism and ventilation in the loggerhead sea turtle. J. 

Exp. Mar. Biol. Ecol. 147: 287.

Lutz, P. L. 1992. Anoxic defense mechanisms in the vertebrate brain. Ann. Rev. Physiol. 54: 601.

Lutz, P. L. 1997. Salt, water, and pH balance in the sea turtle. In: The Biology of Sea Turtles, Vol. I, P. L. Lutz and J. A. 

Musick, eds. CRC Press, Boca Raton, Fla. pp. 343–361.

Lutz, P. L., and G. E. Nilsson. 1997. The Brain without Oxygen, 2nd ed., Landis Press, Austin, Tex.

Lutz, P. L., and T. B. Bentley. 1985. Respiratory physiology of diving in the sea turtle. Copeia 1985: 671.

Lutz, P. L., and A. Dunbar-Cooper. 1987. Variations in the blood chemistry of the loggerhead sea turtle, Caretta 

caretta. Fish. Bull. 85: 37–43.

Lutz, P. L., A. Bergey, and M. Bergey. 1989. The effect of temperature on respiration and acid-base balance in 

the sea turtle Caretta caretta at rest and during routine activity. J. Exp. Biol. 144: 155–169.

Miller, J. D. 1997. Reproduction in sea turtles. In: The Biology of Sea Turtles, Vol. I, P. L. Lutz and J. A. Musick, eds. 

CRC Press, Boca Raton, Fla. pp. 51–81.

Mortimer, J. A. 1990. Factors infl uencing beach sand characteristics on the nesting behavior and clutch 

survival of green turtles (Chelonia mydas). Copeia. 1990: 802.

Mrosovsky, N. 1968. Nocturnal emergence of hatchling sea turtles: Control by thermal inhibition of activity. 

Nature 220: 1338–1339.

Musick, J. A., and C. J. Limpus. 1997. Habitat utilization and migration in juvenile sea turtles. In: The Biology of 

Sea Turtles, Vol. I, P. L. Lutz and J. A. Musick, eds. CRC Press, Boca Raton, Fla. pp. 137–163.

Salmon, M., and B. E. Witherington. 1995. Artifi cial lighting and seafi nding by loggerhead hatchlings: Evidence 

for lunar modulation. Copeia 4: 931.

Salmon, M., and K. J. Lohmann. 1989. Orientation cues used by hatchling loggerhead sea turtles (Caretta 

caretta) during their offshore migration. Ethology 83: 215.

Witham, R. 1991. On the ecology of young sea turtles. Fla. Sci. 54: 179.

Witherington, B. E., K. A. Bjorndal, and C. M. McCabe. 1990. Temporal pattern of nocturnal emergence of 

loggerhead turtle hatchlings from natural nests. Copeia 4: 1165–1168.

27

Chapter 3 Natural and Human Impacts on Turtles

Sarah Milton and Peter Lutz

Key Points

· Sea turtles worldwide are threatened by a variety of natural and human 

(anthropogenic) forces. Because they use of a variety of habitats (beaches to open 

oceans to nearshore environments), sea turtles are vulnerable to human impacts at 

all life stages, although natural mortality is believed to decline with age (increasing 

size).

· Natural mortality factors include the destruction of eggs on the beach by inundation 

or erosion, predation at all life stages, extreme temperatures, and disease.

· The primary cause of mortality among juvenile and adult sea turtles is drowning 

after becoming entangled in fi shing gear, primarily shrimp trawls. Mortality has 

decreased in U.S. waters with the use of turtle excluder devices (TEDs).

· Other signifi cant sources of mortality include direct take (poaching) of eggs and 

turtles and the destruction or degradation of their habitat.

Natural Mortality Factors

Egg Loss 

Turtle eggs are subject to a variety of both natural and anthropogenic impacts. 

High tides or storms can drown the eggs, cause beach erosion, and wash away nests, and 

beach accretion can prevent access between nesting areas and the water. Predation on 

eggs by raccoons, feral hogs, ants, coyotes, and other animals can be quite high. In the 

1970s, before protective efforts began at Canaveral National Seashore, Florida, raccoons 

destroyed 75 to 100 percent of loggerhead nests, although the numbers destroyed on 

most beaches were considerably lower.

Predation

By emerging from the nest at night, turtle hatchlings reduce their risk of predation, but they still must run a gauntlet of predators between the nest and sea—from raccoons, birds, and ghost crabs on shore to tarpon, jacks, sharks, and other fi sh in the waters 

near shore. Although use of turtle hatcheries has fallen out of favor in the United States, 

past hatchery management problems exacerbated predation by fi sh. When hatchlings 

TED - turtle excluder 

device, an adaptation to 

commercial shrimp nets 

to permit sea turtles to 

escape.
28

were regularly released into the water at the same location and same time, predatory fi sh 

would gather in high numbers for their scheduled meal. 

Larger juveniles and adults may be eaten by sharks and other large predatory fi sh, 

though predation decreases as turtles’ size increases. One study indicated that 7 to 75 

percent of tiger sharks sampled in Hawaiian waters inhabited by sea turtles had preyed 

on green turtles.

Hypothermia

Another natural source of mortality in sea turtles is hypothermia. Water temperatures that dip below 8° to 10°C affect primarily juvenile and subadult turtles residing 

in nearshore waters, causing them to become lethargic and buoyant until they fl oat at 

the surface in a condition known as cold-stunning. At temperatures below 5° to 6°C, 

death rates can be signifi cant. The animals can no longer swim or dive, they become 

vulnerable to predators, and they may wash up on shore, where they are exposed to even 

colder temperatures. Large cold-stun events have occurred frequently in recent years 

off the coasts of Long Island, New York; Cape Cod, Massachusetts; and even in Florida. 

Intervention and treatment, such as holding the turtle in warm water and administering 

fl uids and antibiotics, greatly reduces mortality.

Disease

Sea turtles are affected by a number of health problems and diseases. Bacterial 

infections are rare in free-roaming sea turtle populations but higher under captive 

conditions. Parasitic infections are common, however. Up to 30 percent of the Atlantic 

loggerhead population, for example, may be impacted by trematodes that infect the 

cardiovascular system. These heart fl ukes are associated with severe debilitation, muscle 

wasting, and thickening and hardening of major blood vessels. This parasite damage may 

then permit a variety of bacterial infections, including such species as Salmonella and E. 

coli.

Another risk comes from dinofl agellate blooms (red tides), which are occurring in increasing numbers around the world as excess nutrient loads pollute coastal 

waters, conditions that can lead to health problems and mortality in many marine species. Because immediate effects result from aerosol transport, the sea turtles’ mode of 

respiration—inhaling rapidly to fi ll the lungs before a dive—puts them at particular risk. 

Chronic brevetoxicosis, a deadly lung condition caused by red tide dinofl agellates, has 

been suggested as another recent cause of sea turtle mortalities. In Florida, sea turtles 

had neurological symptoms, and the ones that died had measurable brevetoxin levels in 

their tissues. More subtle, long-term effects such as impaired feeding, reduced growth, 

Brevetoxicosis - 

a deadly condition 

caused by ingestion of 

dinofl agellate organisms often responsible 

for red tides; recently 

linked to deaths of 

manatees in Florida 

and common murres in 

California.
29

and immune suppression may occur from consuming prey in which the toxin has bioaccumulated.

By far the most prevalent health problem, however, is a sea turtle disease called 

fi bropapilloma (FP), which has been linked to a herpes virus. FP is typifi ed by large 

fi brous (noncancerous) tumors (Figure 3.1). If external, these tumors can interfere with 

vision, swimming, and diving, and thus hinder the turtle’s ability to feed and escape from 

predators. Internal tumors can affect organ function, digestion, buoyancy, cardiac function, and respiration. Turtles with advanced FP tend to be anemic and have salt imbalances. FP has reached epidemic proportions among green turtles worldwide and has 

been documented in the six other species. Some green turtle populations have infection rates of 65 to 75 percent. The disease rate tends to be higher in environmentally 

degraded areas.

Anthropogenic Impacts

Fisheries By-catch

In a comprehensive review of sources of sea turtle mortality conducted by the 

National Research Council (1990), incidental capture of turtles in shrimp trawls was 

determined to account for more deaths than all other human activities combined (Figure 

3.2). Because of sea turtles’ exceptional breath-holding capabilities, the large numbers 

of deaths blamed on incidental catch (i.e., drowning) was at fi rst greeted with skepticism. 

However, a variety of fi eld and laboratory studies on the effects of forced (versus voluntary) submergence soon demonstrated the vulnerability of sea turtles to trawl nets. One 

study, for example, showed that mortality was strongly dependent on trawl times: mortality increased from 0 percent with trawl times less than 50 minutes to 70 percent after 

90 minutes. Since the enactment of turtle excluder device (TED) regulations, mortalities 

due to shrimp trawling have decreased signifi cantly in U.S. coastal waters—in South 

Carolina alone, mortalities decreased 44 percent. Regrettably, regulation, compliance, 

and enforcement are lower in other nations.

In addition to trawl entanglement, sea turtles have been killed after becoming 

entangled in other types of fi shing gear, such as purse seines, gill nets, longlines (hook 

and line), and lobster or crab pot lines. The longline fi sheries of the Pacifi c are currently a 

signifi cant source of sea turtle mortality, especially among leatherbacks. In other waters 

of the world, such as the Mediterranean, such fi sheries impact other turtle species as 

well. Vessels themselves are another threat. Between 1986 and 1988, 7.3 percent of all 

sea turtle strandings documented in U.S. Atlantic and Gulf of Mexico waters sustained 

some type of propeller or collision injuries, though how much damage was post-mortem 

Fibropapilloma - 

a tumor-forming, 

debilitating, and often 

fatal, disease of sea 

turtles, manifested by 

formation of multiple 

fi brous masses of tissue 

1 mm to 30 cm in 

diameter growing from 

the eyes, fl ippers, neck, 

tail, and scutes and in 

the mouth.

Figure 3.1 A green turtle with 

fi bropapilloma tumors at the base 

of its fl ippers. Photo courtesy of 

Patricia Sposato, Florida Atlantic 

University.

Figure 3.2 Trawl-caught sea 

turtles off Cape Canaveral, 

Florida. Photo courtesy of Dr. 

Peter Lutz, Florida Atlantic 

University.
30

versus cause of death could not be determined. The highest numbers of deaths occur 

where boat traffi c is highest, the Florida Keys and the U.S. Virgin Islands.

Poaching

While the taking of adult sea turtles is rare in the continental United States and 

Hawaii, egg poaching may be signifi cant on some beaches, and in many other parts of 

the world the harvest of both eggs and turtles is high. In some developing countries, the 

need for protein and income generated by the sale of turtle products—even where sea 

turtles are protected—undermines conservation efforts. Breeding aggregations, nesting 

females, and eggs provide ready access to large numbers of turtles. 

Egg collection and hunting are primary causes of green and hawksbill turtle 

mortality worldwide (though all species are affected to some extent). Green turtles are 

exploited primarily for their meat and cartilage (called calipee), while hawksbills are 

taken mainly for their beautiful shells, which are used to create a variety of tortoiseshell 

objects such as jewelry and combs. During the twentieth century, the major importers 

of sea turtle shell and other products were Japan, Hong Kong, Taiwan, and some 

European nations. Thirty years ago, more than 45 nations exported turtle products: the primary exporter was Indonesia, with Panama, Cuba, Mexico, Thailand, 

the Philippines, Kenya, Tanzania, and other countries contributing signifi cantly. 

Today, the market in turtle products continues, especially in Southeast Asia.

Besides direct take, poaching activities have many indirect impacts on sea 

turtles that affect every life stage, primarily habitat degradation or destruction.

Alteration of Nesting Beaches

Anthropogenic impacts on nesting beaches may affect nesting females, eggs, and 

hatchlings. Beach armoring, such as seawalls, rock revetments, and sandbagging installed 

to protect oceanfront property, may prevent females from accessing nesting beaches. In 

some areas, sand may erode completely on the ocean side of structures, leaving no nesting beach at all (Figure 3.3). Where erosion is extensive, property owners or government 

agencies may try to restore the beach by replenishing the sand supply from offshore or 

inland sources. While preferable to beach armoring, such beach renourishment projects 

may cause sea turtle mortality as the result of offshore dredging, and nests already on the 

beach can be buried by the new sand. Mortalities can be reduced by monitoring dredge 

operations and relocating nests to other beach areas.

Other effects of beach nourishment are that renourished beaches may become 

too compacted for nesting and steep, impassable escarpments may form. In addition, the 

replacement sand can have different physical properties than the original, altering critical 

aspects such gas diffusion, moisture content, and temperature, which can affect hatchling 

beach 

renourishment - 

replenishment of beach 

sand by mechanically 

dumping or pumping 

sand onto an eroded 

beach; also referred to 

as beach nourishment.

Calipee - cartilage

Figure 3.3 On a nesting beach 

in North Carolina, homeowners 

placed sandbags to halt erosion, 

rendering previous turtle nesting 

sites inaccessible to sea turtles. 

Photo courtesy of Matthew 

Godfrey, North Carolina Wildlife 

Resources Commission.
31

sex ratios. In sea turtles, like many reptiles, the sex of the hatchling is determined by 

incubation temperature; cooler nest temperatures produce mostly males and warmer 

temperatures produce mostly females.

Near beaches, light from condominiums, streetlights, and swimming pools 

also affects sea turtles (Witherington and Martin, 2000). Excess lighting deters females 

from nesting, while hatchlings emerging from the nest tend to move toward the bright 

artifi cial lights rather than toward the surf. Disoriented, the hatchlings can succumb to 

exhaustion, dehydration, and predation; become entrapped in swimming pools; or be 

crushed by cars or beach vehicles.

High levels of egg poaching, predation, erosion, artifi cial lighting, and heavy 

beach usage have been used to justify relocating nests to other beach sites, or in rare 

cases to hatcheries. While the practice may save threatened nests, it is important to note 

that, compared to nests left in place, relocation decreases nest success due to changes 

in incubation conditions, mortality during the move, and problems such as increased 

predation at release sites.

Pollution and Garbage 

While direct effects on sea turtles of pollutants such as fertilizers and pesticides 

are almost completely unknown, some indirect effects are more obvious, such as habitat 

degradation. Excess nutrients in coastal waters increase the outbreaks of harmful algal 

blooms (HABs), which may affect sea turtle health directly, such as during red tide events, 

or indirectly. Indirect effects include a general degradation of turtle habitat, such as the 

loss of seagrass beds due to decreased light penetration, and the (mostly unknown) 

potential for long-term effects on sea turtle health and physiology. The toxic dinofl agellate Prorocentrum, for example, lives on on seagrasses so it is consumed 

by foraging green turtles. This dinofl agellate is of particular interest 

because it produces a tumor-promoting toxin (okadaic acid) that has 

been found in the tissues of Hawaiian green turtles with fi bropapilloma 

disease.

The effects of garbage in the water and on beaches are more 

direct. Turtles ingest plastics and other debris and become entangled in 

debris such as discarded fi shing line (Figure 3.4). Ingesting plastic can 

cause gut strangulation, reduce nutrient uptake and increase the absorbance of various chemicals in plastics and other debris. The range of 

trash found in sea turtle digestive tracts is impressive: plastic bags, sheeting, beads, and pellets; rope; latex balloons; aluminum; paper and cardboard; styrofoam; 

fi sh hooks (Figure 3.5); charcoal; and glass. Leatherback turtles are particularly attracted 

to plastic bags, which they may mistake for their usual prey, jellyfi sh. Loggerheads—

indeed, any hungry turtle—will eat nearly anything that appears to be the right size.

Figure 3.4 A hawksbill turtle 

entangled in plastic line and 

fi shing net. Photo courtesy of 

Chris Johnson, Marinelife Center 

of Juno Beach, Florida.
32

Table 3.1 A summary of natural and anthropogenic impacts on sea turtles.

Source of Mortality

Primarily 

Anthropogenic Main Life Stage Affected Impact

Shrimp trawling Yes Juveniles/adults High

Predation (natural) No Eggs, hatchlings High

Artificial lighting Yes Nesting females, hatchlings High

Disease No Subadults High for greens

Beach use Yes Nesting females, eggs High on some beaches

Other fisheries Yes Juveniles/adults Medium

Vessel-related injuries, including 

propellers

Yes Juveniles/adults Medium

Poaching Yes Eggs, juveniles, adults Low to medium

Beach development Yes Nesting females, eggs Low to medium

Cold-stunning No Juveniles, subadults Low

Entanglement Yes Juveniles/adults Low

Power plant entrainment Yes Juveniles/adults Low

Oil platform removal Yes Adults Low

Beach renourishment Yes Eggs Low with monitoring

Debris ingestion Yes Juveniles/adults Unknown

Toxins Yes Unknown Unknown

Habitat degradation Yes Hatchlings through adults Unknown

Source: Adapted from National Research Council 1990.

For Further Reading

Aguirre, A. A., and P. L. Lutz. In press. Marine turtles as sentinels of ecosystem health: Is fi bropapillomatosis an 

indicator? Ecosystem Health.

Balazs, G. H., and S. G. Pooley 1993. Research plan to assess marine turtle hooking mortality: Results of 

an expert workshop held in Honolulu, Hawaii. G. H. Balazs and S. G. Pooley, eds., U.S. Dept. of Commerce, 

Administrative Report H-93-18, Silver Spring, Md.

Bjorndal, K. A., A. B. Bolten, and C. J. Lagueux. Ingestion of marine debris by juvenile sea turtles in coastal 

Florida habitats. Mar. Poll. Bull. 28: 154.

Burkholder, J. M. 1998. Implications of harmful microalgae and heterotrophic dinofl agellates in management 

of sustainable marine fi sheries. Ecol. Applic. 8: S37–S62.

Carminati, C. E., E. Gerle, L. L. Kiehn, and R. P. Pisciotta. Blood chemistry comparison of healthy vs. hypothermic 

juvenile Kemp’s ridley sea turtles (Lepidochelys kempii). In: Proc. 14th Ann. Workshop on Sea Turtles Conservation 

and Biology, K. A. Bjorndal, A. B. Bolten, and D. A. Johnson, compilers. NMFS Tech. Memo. NOAA-TM-NMFSSEFSC-351, Miami, Fla., p. 203.

Figure 3.5 This X-ray image of 

a juvenile green turtle shows 

fi shing hooks and other tackle 

in throat. The turtle underwent 

surgery and was released after 

recovering. Photo courtesy of 

Chris Johnson, Marinelife Center 

of Juno Beach, Florida.
33

Carr, A. 1987. Impact of non-degradable marine debris in the ecology and survival outlook of sea turtles. Mar. 

Poll. Bull. 18: 352–356.

Cray, C., R. Varela, G. Bossart, and P. L. Lutz. 2001. Altered in vitro immune responses in green turtles with 

fi bropapillomatosis. J. Zoo. Wildl. Med. 32(4): 436–440.

Ehrhart, L. M. 1991. Fibropapillomas in green turtles of the Indian River lagoon, Florida: Distribution over time 

and area. In: Research Plan for Marine Turtle Fibropapilloma, G. H. Balazs and S. G. Pooley, eds. NMFS Tech. Memo. 

NOAA-TM-NMFS-SWFC-156, Honolulu, Hi. 59.

George, R. H. 1997. Health problems and diseases of sea turtles. In: The Biology of Sea Turtles, Vol. I, P. L. Lutz and 

J. A. Musick, eds., CRC Press, Boca Raton, Fla. pp. 363–385.

Henwood, T. A., and W. E. Stuntz. 1987. Analysis of sea turtle captures and mortalities during commercial 

shrimp trawling. Fish. Bull. 85: 813.

Herbst, L. H. 1994. Fibropapillomatosis of marine turtles. Ann. Rev. Fish Dis. 4: 389.

Herbst, L. H., and P. A. Klein. 1995. Green turtle fi bropapillomatosis: Challenges to assessing the role of environmental cofactors. Environ. Health Perspect. 103(Suppl. 4): 27–30.

Jacobson, E. R., J. L. Marsell, J. P. Sundberg, L. Hajjar, M. C. Reichmann, L. M. Ehrhart, M. Walsh, F. Murru. Cutaneous 

fi bropapillomas of green turtles (Chelonia mydas). J. Comp. Pathol. 101(1): 39–52.

Landsberg, J. H., G. H. Balazs, K. A. Steidinger, D. G. Baden, T. H. Work, and D. J. Russell. The potential role of 

natural tumor promoters in marine turtle fi bropapillomasis. J. Aquat. Anim. Health, 11: 199–210.

Lutcavage, M.E., P. Plotkin, B. Witherington, and P.L. Lutz. 1997. Human impacts on sea turtle survival. In: The 

Biology of Sea Turtles, Vol. I, P. L. Lutz and J. Musick, eds. CRC Press. Boca Raton, Fla. pp. 387–410.

Lutz, P. L., and A. A. Alfaro-Shulman. 1991. The effects of chronic plastic ingestion on green sea turtles. Report 

NOAASB21-WCH06134, U.S. Dept. of Commerce, Miami, Fla.

Mack, D., N. Duplaix, and S. Wells. 1982. Sea turtles, animals of divisible parts: International trade in sea turtle 

products. In: Biology and Conservation of Sea Turtles, K. Bjorndal, ed. Smithsonian Institution Press, Washington, 

D.C.

Meylan, A. B., and S. Sadove. 1986. Cold-stunning in Long Island Sound, New York. Mar. Turtle Newsl. 37: 7–8.

Milton, S. L., A. A. Schulman, and P. L. Lutz. 1997. The effect of beach renourishment with aragonite versus 

silicate sand on beach temperature and loggerhead sea turtle nesting success. J. Coast. Res. 13(3): 904–915.

Milton, S. L., and P. L. Lutz. 2002. Physiological and genetic responses to environmental stress. In: The Biology of 

Sea Turtles, Vol. II, P. L. Lutz, J. A, Musick, and J. Wyneken, eds. CRC Press, Boca Raton, Fla. pp. 159–194.

Morreale, S. J., A. B. Meylan, S. S. Sadove, and E. A. Standora. Annual occurrence and winter mortality of marine 

turtles in New York waters. J. Herpetol. 26(3): 301–308, 1992.

National Research Council. 1990. Decline of the Sea Turtles: Causes and Prevention. National Academy Press, 

Washington, D.C. 259 p.

O’Shea, T. J., G. B. Rathburn, R. K. Bonde, C. D. Buergelt, and D. K. Odell. 1991. An epizootic of Florida manatees 

associated with a dinofl agellate bloom. Mar. Mammal Sci. 7(2): 165–179.

Plotkin, P. T., M. K. Wicksten, and A. F. Amos. 1993. Feeding ecology of the loggerhead sea turtle Caretta caretta

in the northwestern Gulf of Mexico. Mar. Biol. 115: 1.

Pugh, R. S., and P. R. Becker. 2001. Sea turtle contaminants: A review with annotated bibliography. NISTIR 6700, 

Charleston, S.C.

Redlow, T., A. Foley, and K. Singel. 2002. Sea turtle mortality associated with red tide events in Florida. In: 

Proceedings of the 22nd Annual Symposium on Sea Turtle Biology and Conservation, J. Seminoff, compiler. U.S. 

Dept. of Commerce, NOAA Tech. Memo. NMFS-SEFSC, Miami, Fla.
34

Schwartz, F. J. 1978. Behavioral and tolerance responses to cold water temperatures by three species of sea 

turtles (Reptilia, Cheloniidae) in North Carolina. Florida Mar. Res. Publs. 33: 16–18.

Stabenau, E. K., T. A. Heming, and J. F. Mitchell. 1991. Respiratory, acid-base and ionic status of Kemp’s ridley sea 

turtles (Lepidochelys kempi) subjected to trawling, Comp. Biochem. Physiol. 99A: 107–111.

Stancyk, S. E. 1982. Non-human predators of sea turtles and their control. In: Biology and Conservation of Sea 

Turtles, K. A. Bjorndal, ed. Smithsonian Institution Press, Washington, D.C. pp. 139-152.

Witherington, B. E., and L. M. Ehrhart. 1989. Hypothermic stunning and mortality of marine turtles in the Indian 

River lagoon system, Florida. Copeia 1989: 696–703.

Witherington, B. E., and R. E. Martin. 2000. Understanding, assessing, and resolving light-pollution problems on 

sea turtle nesting beaches, 2nd ed. Rev. Florida Marine Research Institute Technical Report TR-2. 73 p.

Witherington, B. E., and M. Salmon. 1992. Predation on loggerhead turtle hatchlings after entering the sea. J. 

Herpetol. 26(2): 226–228.

Wyneken, J., and M. Salmon. 1996. Aquatic predation, fi sh densities, and potential threats to sea turtle 

hatchlings from open-beach hatcheries: Final report. Technical Report for the Broward County, Department of 

Natural Resource Protection, Tech. Report No. 96-04, Fort Lauderdale, Fla.
35

Chapter 4 Oil Toxicity and Impacts on Sea Turtles

Sarah Milton, Peter Lutz, and Gary Shigenaka

Key Points

· Although surprisingly robust when faced with physical damage (shark attacks, boat 

strikes), sea turtles are highly sensitive to chemical insults such as oil.

· Areas of oil and gas exploration, transportation, and processing often overlap with 

important sea turtle habitats.

· Sea turtles are vulnerable to the effects of oil at all life stages—eggs, post-hatchlings, 

juveniles, and adults in nearshore waters.

· Several aspects of sea turtle biology and behavior place them at particular risk, 

including a lack of avoidance behavior, indiscriminate feeding in convergence zones, 

and large predive inhalations.

· Oil effects on turtles include increased egg mortality and developmental defects, 

direct mortality due to oiling in hatchlings, juveniles, and adults; and negative 

impacts to the skin, blood, digestive and immune systems, and salt glands.

Although oil spills are the focus of this book, it would be misleading to portray 

them as the most signifi cant danger to the continued survival of sea turtles, either in 

U.S. waters or worldwide. In 1990, the National Research Council qualitatively ranked 

sources of sea turtle mortality by life stage. The highest mortalities on juvenile and adult 

turtles were caused by commercial fi sheries, on hatchlings it was nonhuman predation 

and beach lighting, and on eggs, nonhuman predators. While “toxins” appeared as a 

listed source, their impact to all three turtle life stages was unknown. Oil spills were not 

considered as a specifi c potential impact, but their absence should not be construed as 

lack of a spill-related threat. Spills that have harmed sea turtles have been documented 

and case studies of those spills are described in Chapter 6. Moreover, it is not diffi cult to 

imagine a large spill washing ashore on a known nesting beach for an endangered sea 

turtle species when females are converging to nest or eggs are hatching. 

Oil spills are rare events, but they have the potential to be spectacularly devastating to resources at risk. In addition, it is not simply infrequent or episodic spills that 

threaten sea turtles. Continuous low-level exposure to oil in the form of tarballs, slicks, 

or elevated background concentrations also challenge animals facing other natural and 

anthropogenic stresses. Chronic exposure may not be lethal by itself, but it may impair a 

turtle’s overall fi tness so that it is less able to withstand other stressors.

What do we know about the toxicity of oil to sea turtles? Unfortunately, not 

much. Direct experimental evidence is diffi cult to obtain, because all sea turtle species 
36

are listed as threatened or endangered under the 1973 U.S. Endangered Species Act 

(Table 1.1). The tenuous status of sea turtles worldwide has signifi cantly infl uenced 

research activities and is a key reason that basic information about the toxicity of oil to 

turtles is scarce. According to Lutz (1989),“Studies on sea turtles must take fully into 

account that all species are at risk and have either threatened or endangered species 

status. Investigation must be confi ned to sublethal effects that are fully reversible once 

the treatment is halted. This restricts the scope of toxicity studies that can be carried out, 

especially the study of internal effects, and investigations of natural defense mechanisms 

... would be very diffi cult.”

Notwithstanding ethical or legal arguments over exposing organisms to potentially harmful materials in order to document effects, from a response and operational 

perspective the lack of data impairs decision-making on trade-offs during oil spills. Fritts 

et al. (1983) concluded two decades ago that the dearth of basic scientifi c information 

about sea turtles complicates the detection of oil-related problems and non-oil-related 

problems. While much has been learned since then, it is still true that determining the 

source of stress to sea turtles is complicated and diffi cult.

Most reports of oil impact are anecdotal or based on small sample sizes, but 

there is no question that contact with oil negatively impacts sea turtles. Because they are 

highly migratory—spending different life-history stages in different habitats—sea turtles 

are vulnerable to oil at all life stages: eggs on the beach, post-hatchlings and juveniles 

in the open ocean gyres, subadults in nearshore habitats, and adults migrating between 

nesting and foraging grounds. Severity, rate, and effects of exposure will thus 

vary by life stage. Unfortunately, areas of oil and gas exploration, transportation, and processing often overlap with important sea turtle habitats, including 

U.S. waters off the Florida and Texas coasts and throughout the Gulf of Mexico 

and the Caribbean.

In this chapter, research on the toxicity of oil to sea turtles is summarized, along with indirect impacts that might occur during an oil spill and 

subsequent cleanup methods. 

Toxicity Basics

It is necessary to begin the discussion of oil toxicity by defi ning what we mean 

by “oil.” One universal challenge facing resource managers and spill responders when 

dealing with oil spills is that oil is a complex mixture of many chemicals. The oil spilled in 

one incident is almost certainly different from that spilled in another. In addition, broad 

categories such as crude oil or diesel oil contain vastly different ingredients, depending 

on the geologic source, refi ning processes, and additives incorporated for transportation. 

Even if we could somehow stipulate that all spilled oil was to be of a single fi xed chemical 

formulation, petroleum products released into the environment are subjected to biologiFigure 4.1 A juvenile green 

turtle oiled during a spill in 

Tampa Bay, Florida, in 1993. 

The turtle was rehabilitated by 

the Clearwater Aquarium and 

eventually released. Photo 

courtesy of Dr. Anne Meylan, 

Florida Fish and Wildlife 

Conservation Commission, 

Florida Marine Research 

Institute.
37

cal, physical, and chemical processes—called weathering— that immediately begin 

altering the oil’s original characteristics. As a result, samples of oil from exactly the same 

source can be very different in composition after exposure to a differing mix of environmental infl uences. Thus, while we generalize about oil toxicity to sea turtles in this book, 

the reader should be aware of the limitations in doing so.

Oil affects different turtle life stages in different ways. Unlike many other organisms, however, each turtle life stage frequents a habitat with notable potential to be 

impacted during an oil spill. Thus, information on oil toxicity is organized by life stage.

The earlier life stages of living marine resources are usually at greater risk from an 

oil spill than adults. The reasons for this are many, but include simple effects of scale: for 

example, a given amount of oil may overwhelm a smaller immature organism relative to 

the larger adult. The metabolic machinery an animal uses to detoxify or cleanse itself of 

a contaminant may not be fully developed in younger life stages. Also, in early life stages 

animals may contain a proportionally higher concentration of lipids, to which many 

contaminants such as petroleum hydrocarbons bind.

Eggs and Nesting

While eggs, embryos, and hatchlings are likely to be more vulnerable to volatile 

and water-soluble contaminants than adults, only one study has directly examined the 

effects of oil compounds on sea turtle eggs. Following the 1979 Ixtoc 1 blowout in the 

Bay of Campeche, Mexico, Fritts and McGehee (1981) collected both fi eld and laboratory data on the spill’s effects on sea turtle nests from an impacted beach. In laboratory 

experiments where fresh oil was poured on nests of eggs during the last half to last quarter of the incubation period, the researchers found a signifi cant decrease in survival to 

hatching. Eggs oiled at the beginning of incubation survived to hatching, but the hatchlings had developmental deformities in the form of signifi cant deviations in the number 

of scutes. Weathered oil, however, appeared to lose its toxic effect on eggs: oiled sand 

taken from the beach the year following the spill did not produce measurable impacts on 

hatchling survival or morphology. The data thus suggest that oil contamination of turtle 

nesting sites would be most harmful if fresh oil spilled during the nesting season. 

On the other hand, Fritts and McGehee also concluded that oil spilled even a 

few weeks prior to the nesting season would have little effect on egg development and 

hatchling fi tness. A threshold level of oiling to produce measurable effects on survival 

of loggerhead embryos was not determined; however, a mixture of 7.5 ml of oil per kg 

of sand did not signifi cantly reduce survival. The way oil was introduced into a nest 

did affect toxicity. Oil poured on top of a clutch of eggs, versus that mixed thoroughly 

into the sand, had greater impact. That is, 30 ml of oil poured onto the sand over eggs 

lowered survival in embryos, whereas 30 ml of oil mixed into the sand around the eggs 

Weathering - 

the alteration of the 

physical and chemical 

properties of spilled oil 

through a series of natural biological, physical, 

and chemical processes 

beginning when a spill 

occurs and continuing as long as the oil 

remains in the environment. Contributing 

processes include 

spreading, evaporation, 

dissolution, dispersion, 

photochemical oxidation, emulsifi cation, 

microbial degradation, adsorption to 

suspended particulate 

material, stranding, or 

sedimentation.
38

did not. The authors speculated oil on the sand surface created an exposure gradient in 

which lethal concentrations were experienced by individual eggs, but not all of them.

The effects of beach oiling on nesting females’ behavior and physiology were 

not investigated. Females may refuse to nest on an oiled beach, and crossing it could 

cause external oiling of the skin and carapace. Fritts and McGehee noted that the oil 

behaved like any other fl otsam; not all beach areas received equal amounts, and most of 

it was deposited just above the high-tide line. The latter point is signifi cant for planning 

and response because most turtles nest well above the high-tide level. One implication of nesting behavior is that under normal circumstances, nest sites are less likely to 

be directly affected by stranding oil. Spills, however, are often associated with storms 

or exceptional tides, which may deposit oil at higher than normal levels. In addition, 

beached oil would lie between nests and the water, thus females coming ashore to lay 

eggs or emerging hatchlings would risk exposure as they traversed the beach.

Phillott and Parmenter (2001) determined that oil covering different portions 

and different proportions of the surface of sea turtle eggs affects hatching success. For 

example, an egg’s upper hemisphere is the primary gas exchange surface during early 

incubation. If oil covers enough of the upper surface to impede gaseous exchange, 

higher mortality in embryos will occur. Larger eggs are more likely to survive than smaller 

eggs. Physical smothering effects of oil therefore represent a threat to nest viability, even 

if the oil has low inherent toxicity.

Three important factors—nest temperature, gas exchange, and moisture—affect 

hatching success. Oil can potentially impact a nesting beach by interfering with gas 

exchange within the nest (oil-fi lled interstitial spaces, for example, would prevent oxygen 

from diffusing through the sand into the nest); altering the hydric environment (sea turtle 

nests need sand that is not too wet or too dry); and altering nest temperature by changing the color or thermal conductivity of the sand. 

Hatchlings

Once hatchling turtles successfully reach the water, they are subject to the same 

kinds of oil spill exposure hazards as adults (see page 39). However, relative size, lack of 

motility, and swimming and feeding habits increase the risk to recently hatched turtles. 

The increased risks can be linked to the following factors, among others:

· Size. A hatchling encountering the same tar patty or oil slick as an adult has a greater 

probability of being physically impaired or overwhelmed.

· Motility. Most reports of oiled hatchlings originate from convergence zones, ocean 

areas where currents meet to form collection points for material at or near the 

surface of the water. These zones aggregate oil slicks as well as smaller, weaker sea 

turtles. For a weakly motile organism such as a young turtle, a Langmuir cell, where 

Langmuir cell - 

individual counterrotating vortices (i.e., 

one rotates clockwise, 

the next counter 

clockwise, the next 

clockwise, etc.), resulting in the commonly 

observed “windrows” 

in which fl otsam is 

arranged in rows 

paralleling the wind 

direction. At boundaries between the cells, 

water is moving either 

up or down. Where 

it is moving down, 

the surface water is 

converging (being 

pulled together), and 

any surface objects 

will be pulled into the 

boundary line between 

the cells; where the 

water is moving up 

between the cells, the 

water diverges, and no 

material collects.
39

surface currents collide before pushing down and around, represents a virtually 

closed system where the turtle can easily become trapped.

· Surface swimming. Because hatchlings spend a greater proportion of their time at 

the sea surface than adults, their risk of exposure to fl oating oil slicks is increased.

The physical processes and behaviors that place sea turtles at risk during spills 

also pose threats from non-spill-related petroleum sources. Tarballs, for example, are a 

byproduct of normal and accepted ship operations (e.g., bilge tank fl ushing), are illegally 

discharged from tank washings and other shipboard operations, and are even released 

naturally from coastal oil seeps. They are found in every ocean and on every beach; 

features such as convergence zones and Langmuir cells can aggregate even widely 

dispersed tarballs into an area where sea turtles concentrate. Oil exposure is therefore a 

threat to sea turtles both in the presence and in the absence of an identifi ed spill.

Non-spill-associated tarballs are likely to be more weathered than those derived 

from a spill, mostly due to differences in time spent on the water. While less toxic to 

eggs and embryos than freshly spilled oil, weathered oil can have signifi cant impacts 

on hatchlings. Hatchlings that contact oil residues while crossing a beach can exhibit a 

range of effects, from acute toxicity to impaired movement and normal bodily functions. 

In convergence zones off the east coast of Florida, tar was found in the mouths, esophagi, 

or stomachs of 65 out of 103 post-hatchling loggerheads (Loehefener et al. 1989). In 

another study (Witherington 1994), 34 percent of post-hatchlings at “weed lines” off the 

Florida coast had tar in their mouths or esophagi, and over half had tar caked in their 

jaws. Lutz (1989) reported that hatchlings have been found apparently starved to death, 

their beaks and esophagi blocked with tarballs. Hatchlings sticky with oil residue may 

have a more diffi cult time crawling and swimming, rendering them more vulnerable to 

predation.

Whether hatchlings, juveniles, or adults, tarballs in a turtle’s gut are likely to have 

a variety of effects—starvation from gut blockage, decreased absorption effi ciency, 

absorption of toxins, effects of general intestinal blockage (such as local necrosis or 

ulceration), interference with fat metabolism, and buoyancy problems caused by the 

buildup of fermentation gases (fl oating prevents turtles from feeding and increases their 

vulnerability to predators and boats), among others.

Juveniles/Adults 

Studies of oil effects on loggerheads in a controlled setting (Lutcavage et al. 

1995) suggest that all post-hatch life stages are vulnerable to oil effects and tar ingestion because sea turtles show no avoidance behavior when they encounter an oil slick. 

Turtles also indiscriminately eat anything that registers as being an appropriate size for 

food, including tarballs. Such was the case with a juvenile loggerhead stranded in Gran 
40

Canaria, Spain, which had an esophageal defect that trapped tarballs, plastics, and fi shing line in its digestive system. The large esophageal swelling displaced the liver and 

intestines, causing severe tissue swelling near the stomach. The turtle was nearly starved, 

and it had buoyancy problems and a bacterial infection (most likely secondary to its poor 

physical condition).

Sea turtles’ diving behavior also puts them at risk. They rapidly inhale a large 

volume of air before diving and continually resurface over time. Adults doing this in an 

oil spill would experience both extended physical exposure to the oil and prolonged 

exposure to petroleum vapors, the most acutely harmful phase of a spill. Compared to 

hatchlings, however, juveniles and adults spend less time at the sea surface, which potentially reduces their chances of exposure from a smaller oil slick.

Oil ingested by a turtle does not pass rapidly through its digestive tract. It may be 

retained for several days, increasing internal contact and the likelihood that toxic compounds will be absorbed. The risk of gut impaction also increases for turtles that have 

ingested oil.

Anecdotal accounts of dead or impaired green turtles found with tarballs in their 

mouths were summarized by Witham (1978). Three turtles found dead after the Ixtoc 1 

blowout showed evidence of oil externally and in the mouth, esophagus, and small 

intestine, although there was no evidence of lesions in the gastrointestinal tract, trachea, 

or lungs (Hall et al. 1983). However, chemical analysis of tissue showed a chronic exposure 

to and selective accumulation of hydrocarbons. Some were concentrated 15 times higher 

than reference levels. Hall et al. believed prolonged exposure to oil may have caused the 

poor body condition of the animals by disrupting feeding.

Laboratory Studies

The only laboratory work investigating the direct impacts of oil on sea turtle 

health and physiology performed to date was part of comprehensive, multi-facility study 

conducted for the U.S. Minerals Management Service (MMS) in 1986 (Lutcavage et al. 

1995). A conceptual framework for considering behavioral and physiological oil impacts 

was summarized by Lutz (1989) in a series of diagrams, two of which are reproduced here 

as Figures 4.2 and 4.3.

The Lutcavage et al. experiments on physiological and clinicopathological effects 

of oil on loggerhead sea turtles approximately 15 to 18 months old showed that the 

turtles’ major physiological systems are adversely affected by both chronic and acute 

exposures (96-hour exposure to a 0.05-cm layer of South Louisiana crude oil versus 0.5 

cm for 48 hours). The skin of exposed turtles, particularly the soft pliable areas of the neck 

and fl ippers, sloughed off in layers. This continued for one to two weeks into the recovery 

period. Histological examination of the damaged skin showed proliferation of infl amed, 

MMS - U.S. Minerals 

Management Service 

(U.S. Department of the 

Interior).
41

Figure 4.2 Conceptual 

framework of sea turtle 

behavioral responses to oil 

exposure (adapted from Lutz 

1989).

Figure 4.3 Conceptual 

framework for the effects of oil 

exposure to sea turtles (adapted 

from Lutz 1989).

Oil

Avoidance behavior

Partial avoidance

No behavior change

Minimal direct contact

and "no" effects

Direct contact reduced

(Time submerged increases)

Fewer physiological effects

Direct contact Physiological effects

Lungs

Skin

Gut

Sense

organs

Route

Oil/Dispersant

Carcinogenesis

Parasitism, disease

Aerobic scope decreased

Dive time increased

Assimilation decreased

Internal effects

Interference

Nesting Abnormal development

beach

Viability decreased

Foraging time

reduced

Organ dysfunction

Hormone balance

disturbed

Death

Predation

increased

Growth

reduced

Performance

depressed

Reproduction

decreased

Behavior

changed

Death

Result
42

abnormal, and dead cells. Recovery from the sloughing skin and mucosa took up to 21 

days, increasing the turtle’s susceptibility to infection.

Oil was also detected in the nares, eyes, upper esophagus, and feces, indicating 

that turtles were ingesting oil, though apparently not enough to cause intestinal bleeding and anemia. Ingestion would almost certainly have been greater if the turtles had 

been fed during the experimental period.

Internal effects of oil exposure include signifi cant changes in blood and blood 

chemistry. Hematocrits (red blood cell volume) decreased nearly 50 percent in oiled 

turtles and did not increase again during the recovery period, though the presumed 

decrease in oxygen carrying capacity was not refl ected in changes in blood oxygen or 

respiration. In mammals, changes in red blood cells and their production are associated 

with regenerative anemic conditions. Similar effects have been observed in oiled seabirds, indicating that red blood cells may be a primary target of oil toxicity. An immune 

response was also indicated by signifi cant increases in white blood cells, which by day 3 

of oil exposure were four times higher in oiled turtles than control animals. This increase 

persisted for more than a week.

While vapor inhalation changes the behavior and pathology of marine mammals—as evidenced, for example, by an increase in time spent submerged—such behavior was not evident with turtles. The experimental animals showed no overall avoidance 

behavior, though some were clearly disturbed by the fumes. Some turtles surfaced away 

from the oil in behavioral tests, but they appeared to be avoiding the dark surface, not the 

oil per se.

In vertebrates, the liver is the primary site of chemical detoxifi cation, so it is 

reasonable to expect toxic effects to be evident in changed serum levels of various liver 

enzymes. (Such diagnoses are used in veterinary and human medicine, though their 

signifi cance in turtle health has not yet been ascertained). However, no changes were 

evident in the Lutcavage et al. study, which differed signifi cantly from control animals. 

Changes in some enzyme levels were most likely the result of starvation during the 

experiment (animals were not fed during exposure), since changes were similar in both 

control and experimental animals. Enzyme levels in oiled turtles did not recover as 

quickly once feeding commenced, however.

Since no animals were sacrifi ced during this study, it was not possible to examine 

the turtles for internal damage, except through indirect methods such as measuring 

serum enzyme levels. Potential effects, however, may be extrapolated from investigations 

of dead oiled birds, because reptiles and birds share a common lineage. Following the 

Gulf War, postmortem examinations of 300 birds revealed a variety of damage: gizzard 

impaction due to tarballs, enteritis, starvation, fl uid and hemorrhaging in the lungs, 

damage to the absorptive surface of the intestines, liver degeneration, kidney damage, 

and degeneration of adrenal gland cells (which in turn affects salt gland function in seabirds and possibly turtles). Other studies found high incidences of hemorrhagic enteritis

Hematocrit - red 

blood cell volume.

Hemorrhagic 

enteritis - bleeding 

infl ammation of the 

intestine.
43

in oil-killed birds. Sea turtles may be at particular risk from such problems due to their 

habit of eating anything that fl oats; post-hatchlings, in particular, feed in convergence 

zones, which collect a variety of anthropogenic materials such as tarballs.

Although they found little experimental evidence in the MMS studies to indicate 

bioaccumulation of hydrocarbons by sea turtles, Lutcavage et al. (1995) cited a report by 

Greenpeace from the Gulf War in which high concentrations of petroleum hydrocarbons 

were found in the liver (4,050 mg/kg) and stomach (310 mg/kg) of an oiled green turtle. 

The Lutcavage et al. studies provided qualitative evidence that oil exposure affects the 

balancing of salt and water. Extended salt gland dysfunction would have signifi cant 

negative impacts on turtle health, altering internal salt and water homeostasis. In two 

experimentally oiled turtles, the salt glands effectively shut down for several days, 

although the turtles eventually recovered after the exposure was discontinued. The salt 

glands did not appear to be physically blocked (though this could not be ruled out), so it 

appeared that the impact was toxic, rather than physical.

Indirect Effects of Oil on Sea Turtles

Studies summarized thus far show that oil has a number of direct effects on sea 

turtles. Like any living resource at risk, turtles are susceptible to a number of potential 

indirect impacts, which would generally be less obvious than short-term direct impacts 

such as mortality, but may ultimately cause more harm to populations.

A number of potential indirect impacts can be attributed to the unique biological 

attributes or behaviors of marine turtles. Frazier (1980) suggested that olfactory impairment from chemical contamination could represent a substantial indirect effect in sea 

turtles, since a keen sense of smell apparently plays an important role in navigation and 

orientation. Frazier noted that masking olfactory cues may not harm a turtle outright, 

but impairing its ability to properly orient itself can result in a population impact as signifi cant as direct toxicity—perhaps even greater. A related problem is the possibility that 

an oil spill impacting nesting beaches may affect the locational imprinting of hatchlings, 

and thus impair their ability to return to their natal beaches to breed and nest.

Even if sea turtles avoid direct contact with oil slicks, eating contaminated food 

is a direct exposure path, and reduced food availability is an indirect exposure route. A 

1986 oil spill off Panama, for example, trapped oil in sediments of intertidal beds of turtle 

grass (Thalassia testudinum), killing the seagrass, a signifi cant component of green turtle 

diets. Sediments below the damaged seagrasses subsequently eroded, exposing the 

coralline rock bed. Decreases in invertebrates and sponge populations affect other sea 

turtle species as well, including hawksbills, loggerheads, and ridleys. In this instance, after 

long-term contact with oil many invertebrates were killed and many others declined in 

numbers. A variety of petroleum compounds are toxic to fi sh and invertebrates, although 

the effect is not uniform; different species have different sensitivities to different com-
44

pounds. Some compounds are more toxic than others or are more toxic in different 

combinations (National Research Council 2003). 

Dietary differences can potentially increase or decrease risk from hydrocarbon 

ingestion. Kemp’s ridley and loggerhead turtles, for example, feed primarily on crustaceans and mollusks, which bioaccumulate petroleum hydrocarbons because they cannot 

effi ciently clear contaminants from their bodies. Thus Kemp’s ridleys and loggerheads 

may be at greater risk of exposure by ingesting food than leatherback turtles, which feed 

primarily on coelenterates.

Followup studies on the effects of an oil spill on San Cristóbal in the Galapagos 

Islands suggest an indirect and unanticipated food-related effect on another reptile, the 

marine iguana (Amblyrhynchus cristatus). Although the spill’s short-term impacts were 

minimal, in the year that followed the iguana population of nearby Santa Fe Island suffered a signifi cant mortality, 62 percent. Wikelski et al. (2002) reported that the probable 

cause of this substantial population decline was chronic, low-concentration oil exposure 

to the specialized fermentation bacteria that iguanas carry in their hindguts. The authors 

postulated that oil impacts on these bacteria impaired the iguanas’ ability to process the 

algae they eat. Largely herbivorous sea turtles, like the green, also carry symbiotic bacteria to aid in digestion and are likely to be similarly vulnerable to effects on the bacteria 

observed in the marine iguanas.

Some authors (e.g., Hutchinson and Simmonds 1992) have suggested a link 

between low-level chronic exposure to contaminants such as oil, and the occurrence of 

cutaneous fi bropapilloma disease (Chapter 3). The link was circumstantial; it was based 

on immune system responses to oil exposure observed by Lutcavage et al. (1995) and 

assertions by other pathologists that immune system weakness and aberrant wound 

responses may trigger fi bropapilloma disease. However, the relationship is likely to be 

complex, thus it is unclear which is cause and which effect (L. Herbst 20021

).

Beach sand temperature infl uences sea turtle development and behavior, and 

Hays et al. (2001) determined that subtle differences in sand color or albedo can signifi -

cantly affect underlying temperatures. Because sex determination in turtles is temperature-dependent, shifts in albedo could potentially change hatchling sex ratios. Even light 

surface oiling that does not penetrate directly to the eggs could therefore affect gender 

distribution in a population.

Exposure Risk

Much of the oil spilled in the oceans results in surface contamination along 

ocean tanker lanes and coastal areas, including along the coasts of California,Texas, and 

Florida; Cuba and northwest South America; northern Europe; the Gulf of Arabia and the 

Arabian Sea; and throughout the Indo-Pacifi c region along eastern Asia. Unfortunately, 

the risk of an oil spill affecting a signifi cant nesting beach within U.S. territory is high. Of 

albedo - ratio of 

solar energy refl ected 

from an object to solar 

energy received by it.
45

these higher risk areas, south Florida is particularly vulnerable due to the convergence 

of ocean currents and shipping lanes. Data on wind, loop current, and drifter studies led 

Geo-Marine, Inc. (1980) to predict that oil spilled in the eastern Gulf of Mexico would have 

the highest probability of washing ashore along the southeast coast of Florida between 

Key West and Fort Pierce, an area that also hosts a large percentage of the loggerhead 

sea turtle nests in the southeastern United States. The Sargasso Sea alone is estimated 

to entrap 70,000 metric tons of tar, while a two-year study by Van Vleet et al. (1984) 

indicated that, in general, pelagic tar concentrations in the eastern Gulf of Mexico were 

signifi cantly higher than those reported for other parts of the world.

Because environmental problems do not respect human boundaries, it is not 

surprising that sea turtles found in U.S. waters are vulnerable to spills that occur both 

within and outside U.S. waters. Approximately 1 percent of annual U.S. sea turtle strandings are associated with oil; rates are higher in south Florida (3 percent) and Texas (3 

to 6.3 percent) (stranding statistics are summarized by Lutcavage et al. 1997). Rates of 

contact with pollutants are likely to be much higher than those detected from strandings 

alone; during the 1986 fi shing season off Malta, for example, 17 of 99 loggerhead turtles 

caught by Maltese fi sherman suffered from crude oil contamination, compared to three 

contaminated with plastic or metal litter but not oil (Gramentz 1988).

The consequences of chronic exposure to oil in the form of ingested tarballs is 

not clear, but some evidence exists that this occurrence, alone or in combination with 

other foreign material, can seriously compromise sea turtle health. Torrent et al. (2002) 

examined a juvenile loggerhead captured barely alive off the coast of Gran Canaria, 

Spain. The turtle died in transport and was necropsied. A number of abnormal pathologies were found, including an esophageal diverticulum (an abnormal saclike pouch) 

and an infection by bacteria not normally found in sea turtles. The authors attributed 

the poor condition of the turtle, directly and indirectly, to ingested tarballs, plastic, and 

fi shing line.

For Further Reading

Bedinger, C. A. Jr., and C. P. Nulton. 1982. Analysis of environmental and tar samples from the nearshore south 

Texas area after oiling from the Ixtoc-1 blowout, Bull. Environ. Contam. Toxicol. 28: 166–171.

Butler, J. N., B. F. Morris, and J. Sass. 1973. Pelagic Tar from Bermuda and the Sargasso Sea. The Bermuda 

Biological Station for Research, Cambridge, Mass.

Cubit, J. D. 1993. The effects of the 1986 Bahia Las Minas oil spill on benthic marine biota of shallow reef fl ats. 

In: Proceedings of the Third International Conference “Effects of Oil on Wildlife.” New Orleans, La., Jan. 28–29, p. 

A-14.

Dillon, T. M., J. M. Neff, and J. S. Warner. 1978. Toxicity and sublethal effects of No. 2 fuel oil on the supralittoral 

isopod Lygia exotica. Bull. Environ. Contam. Toxicol. 20: 320–327.

Diverticulum - 

an abnormal saclike 

pouch projecting from 

a defect in the wall of a 

tube or cavity.
46

Florida Institute of Oceanography. 1985. Study of the effects of oil on marine turtles, Vol. 2, Technical Report. 

Final report submitted by the Florida Institute of Oceanography (FIO) to the U.S. Minerals Management 

Service, St. Petersburg, Fla. November. 143 p.

Fritts, T. H., and M. A. McGehee. 1982. Effects of petroleum on the development and survival of marine turtle 

embryos. Contract No. 14-16-0009-80-946, FWS/OBS-82/37. U.S. Fish and Wildlife Service, U.S. Department of 

the Interior, Washington, D.C. 

Geo-Marine, Inc. 1980. A report on if, when and where oil from the Mexican oil well blowout (Ixtoc-1) could 

impact Florida’s coastal waters. Report prepared for the Florida Department of Natural Resources, Tallahassee, 

Fla. 77 p.

Gramentz, D. 1988. Involvement of loggerhead turtles with the plastic, metal, and hydrocarbon pollution in 

the central Mediterranean. Mar. Poll. Bull. 19(1): 11–13.

Hall, R. J., A. A. Belisle, and L. Sileo. 1983. Residues of petroleum hydrocarbons in tissues of sea turtles exposed 

to the Ixtoc I oil spill. J. Wildl. Diseases 19(2): 106–109.

Hays, G. C., J. S. Ashworth, M. J. Barnsley, A. C. Broderick, D. R. Emery, B. J. Godley, A. Henwood, and E. L. Jones. 

2001. The importance of sand albedo for the thermal conditions on sea turtle nesting beaches. Oikos 93(1): 

87–94.

Kira, S., T. Itoh, H. Hayatsu, K. Taketa, Y. Zheng, R. Li, T. L. Holliday, and C. S. Giam. 1994. Detection of waterborne 

mutagens and characterization of chemicals in selected Galveston sites after an oil spill. Bull. Environ. Contam. 

Toxicol. 53: 285–291.

Levings, S. C., S. D. Garrity, and K. A. Burns. 1993. Effects of oil spills on fringing mangroves: Long-term reductions in nursery areas and persistence of toxic oil residues. In: Proceedings of the Third International Conference 

“Effects of Oil on Wildlife.” New Orleans, La., Jan. 28–29, p. A-29.

Loehefener, R. R., W. Hoggard, C. L. Roden, K. D. Mullin, and C. M. Rogers. 1989. Petroleum structures and the 

distribution of sea turtles. In: Proc. Spring Ternary Gulf of Mexico Studies Meeting, Minerals Management Service, 

U.S. Department of the Interior, New Orleans, La.

Lutcavage, M. E., P. L. Lutz, G. D. Bossart, and D. M. Hudson. 1995. Physiologic and clinicopathologic effects of 

crude oil on loggerhead sea turtles. Arch. Environ. Contam. Toxicol. 28: 417–422.

Lutcavage, M. E., P. Plotkin, B. Witherington, and P. L. Lutz. 1997. Human impacts on sea turtle survival. In: The 

Biology of Sea Turtles, Vol. I, P. L. Lutz and J. Musick, eds. CRC Press, Boca Raton, Fla. pp. 387–410.

Lutz, P. L. 1989. Methods for determining the toxicity of oil and dispersants to sea turtles. In: Oil and Dispersant 

Toxicity Testing: Proceedings of a Workshop on Technical Specifi cations Held in New Orleans, La., T. W. Duke and G. 

Petrazzuolo, eds. Prepared under MMS contract 14-12-0001-30447, OCS Study MMS 89-0042, pp. 97–101.

National Research Council. 2003. Oil in the Sea III: Inputs, Fates, and Effects. National Academy Press, Washington, 

D.C. 265 p. + appendices.

Odell, D. K., and C. MacMurray. 1986. Behavioral response to oil. In: Final Report. Study of the Effect of Oil on 

Marine Turtles, S. Vargo, P. L. Lutz, D. K. Odell, T. Van Fleet, and G. Bossart, eds. Minerals Management Service 

Contract Number 14-12-0001-30063, Florida Inst. of Oceanography, St. Petersburg, Fla.

Philott, A. D., and C. J. Parmenter. 2001. Infl uence of diminished respiratory surface area on survival of sea turtle 

embryos. J. Experim. Zool.289(5): 317–321.

Plotkin, P., and A. F. Amos. 1988. Entanglement and ingestion of marine debris by sea turtles stranded along 

the south Texas coast. In: Proc. 8th Ann. Symp. on Sea Turtle Biology and Conservation, NOAA Tech. Memo. NMFSSEFC-214, Miami, Fla.

Rabalais, S. C., and N. N. Rabalais. 1980. The occurrence of sea turtles on the South Texas Coast. Contr. Mar. Sci., 

23: 123–129.

Raloff, J. 1986. When sea turtles are awash in oil. Sci. News, 130(Dec.): 358.
47

Romero, G. C., G. R. Harvey, and D. K. Atwood. 1981. Stranded tar on Florida beaches: September 1979 through 

October 1980. Mar. Poll. Bull. 12: 280–284.

Slade, G. J. 1982. Effects of Ixtoc-I crude oil and Corexit 9527 dispersant on Spot (Leiostomus xanthurus) egg 

mortality. Bull. Environ. Contam. Toxicol. 29: 525–530.

Torrent A., S. Deniz, A. Ruiz, P. Calabuig, J. Sicilia, and J. Oros. 2002. Esophageal diverticulum associated with 

Aeroccus viridans infection in loggerhead sea turtles (Caretta caretta), J. Wildl. Diseases 38(1): 221–223.

Van Vleet, T., and G. G. Pauly. 1987. Characterization of oil residues scraped from stranded sea turtles from the 

Gulf of Mexico. Carib. J. Sci. 23: 77.

Van Vleet, E. S., W. M. Sackett, S. B. Reinhardt, and M. E. Mangini. 1984. Distribution, sources, and fates of fl oating 

oil residues in the eastern Gulf of Mexico. Mar. Poll. Bull. 15: 106–110.

Witham, R. 1978. Does a problem exist relative to small sea turtles and oil spills? In: The Proceedings of the 

Conference on Assessment of Ecological Impacts of Oil Spills, 14-17 June 1978, Keystone Colo. pp. 629–632.

Witherington, B. E. 1994. Flotsam, jetsam, post-hatchling loggerheads, and the advecting surface smorgasbord. In: Proc. 14th Ann. Symp. Sea Turtle Biology and Conservation, K. A. Bjorndal, A. B. Bolten, D. A. Johnson, and 

P. J. Eliazar, compilers. NOAA Tech. Memo. NMFS-SEFSC-351, Miami, Fla. p. 166.

49

Chapter 5 Response Considerations for Sea Turtles

Rebecca Z. Hoff and Gary Shigenaka

Key Points

· Spill responders must consider sea turtle-related tradeoffs in several ways, 

depending on spill location, time of year, and species of turtle.

· Sea turtles are likely to be at greatest risk when they are aggregating, usually peaking 

around nesting and hatching periods, and when they are foraging in convergence 

zones.

· Spill response in sea turtle habitat uses standard techniques, but they are modifi ed 

to accommodate unique features and sensitivities of sea turtle behavior and life 

history.

· Several aspects of sea turtle biology and behavior place them at particular risk, 

including lack of avoidance behavior, indiscriminate feeding in convergence zones, 

and inhalation of large volumes of air before dives.

· While more common as a management technique, intrusive intervention to remove 

turtles or nests should be considered a response measure of last resort.

The preceding chapters have shown that sea turtles are vulnerable to oil exposure by many different routes—primarily due to the unfortunate overlap of habitat 

utilization by turtles and the physical behavior of oil. Turtle habitats include fi ne-grain 

sand beaches (nesting), seagrass beds and coral reefs (foraging), and open water convergence zones and sargassum mats (developmental). These habitats are often the places 

where oil strands or aggregates, hence there is an enhanced potential for sea turtles to 

encounter spilled oil. Since we know that oil harms turtles, reducing exposure should be 

the focus of response actions. As Lutz (1989) noted, “the potentially harmful effects of an 

oil spill on sea turtles must clearly be taken seriously, and any strategy to prevent turtles 

from encountering the oil must be regarded as a preferred frontline defense.”

However, while reducing or preventing turtles from encountering oil is the 

preferred, obvious, and logical strategy, it is not necessarily easy or even possible. No 

response action is 100 percent effective, but any reduction in oil exposure reduces the 

potential stress on threatened sea turtle populations. Spill response planners should 

thus ask the following questions related to sea turtles: 

· What are the open water and shoreline response actions we might consider in the 

event of a spill in an area frequented by sea turtles? 
50

· Given the habitat preferences and unique features of sea turtle life history, do 

we need to modify standard response practices to accommodate sea turtles and 

minimize the impact to their populations? 

· How would we do this? 

· Can we anticipate spill impacts to turtles well enough that contingency plans will 

operationally refl ect what we know? 

NOAA and the U.S. Fish and Wildlife Service (USFWS) share trustee resource 

responsibility under Section 7 of the Endangered Species Act to address any potential 

impacts of a spill response on sea turtles and their critical habitat. Area contingency planning must consider possible impacts to listed species from response activities and how to 

avoid or mitigate them. During an actual response, emergency consultations for Section 

7 concerns would be held to consider specifi c response actions and how they might 

impact sea turtles. Figure 5.1 shows a schematic of how the consultation process works.

Responses to oil spills depend on the product spilled and the environment at risk. 

The general features of spill response equipment and strategies are described in other 

publications.2

 In this chapter, we provide some basic information on response activities 

that might be considered in sea turtle habitat.

Open-Water Response Options

The overlap of oil and habitat also implies that sea turtles may be at increased 

risk from response activities themselves. Some of these activities and their impacts are 

discussed below.

Mechanical Recovery Offshore

Spilled oil on water is contained and collected using equipment such as booms 

and skimmers.3

 At many spills, mechanical collection is relied upon as the primary onwater cleanup method, but experience has shown that mechanical recovery alone cannot 

adequately deal with large spills offshore. Prior to the Exxon Valdez oil spill, average 

mechanical recovery effectiveness was typically estimated at around 10 to 20 percent, 

although it may be up to an average of about 30 percent now (PMG, Inc. 2001). Weather 

and ocean conditions, the nature of the oil, and other factors can limit the effectiveness 

of mechanical recovery. For example, containment booms do not perform well in heavy 

waves, in shallow waters, or in swift currents—an estimated 58 percent of all spills occur 

in water moving over 1 knot (PMG, Inc. 2001). Even under ideal circumstances, mechanical 

recovery may not successfully control large spills or oil that has spread over large areas. In 

such cases, alternative open-water response techniques, such as dispersant application or 

in-situ burning of oil on water, may signifi cantly reduce the time that oil remains on the 

surface, the formation of tarballs, and the risk that oil will reach shore.

Section 7 

consultation - 

requirement under the 

Endangered Species 

Act for federal agencies 

to address potential 

impacts of their actions 

on threatened species.

USFWS - U.S. Fish and 

Wildlife Service (U.S. 

Department of the 

Interior).

In-situ burning - 

response technique 

in which spilled oil is 

burned in place.
51

Figure 5.1 Schematic of Section 7 

endangered species consultation 

process (from U.S. Coast Guard 

2002). Oil

Spill

Notification occurs in

accordance with

NCP & ACP

Listed species or

critical habitat

potentially affected

by response ops?

USFWS/NMFS Endangered

species expertise requested

Endangered species

expertise not required

USFWS and/or NMFS endangered

species expertise provided to

FOSC's Incident Command System

USFWS/NMFS

provide recommendations

to minimize impact

Listed species or

critical habitat

anticipated affected

by response ops?

FOSC closes case,

emergency consultation ends

USFWS/NMFS

continue to provide

recommendations

to avoid impact

Appendix B

information

completed

NO

NO YES

YES

NCP- National 

Contingency Plan.

ACP- Area Contingency 

Plan.

FOSC- Federal OnScene Coordinator.
52

The timing of a spill would defi ne the threat to turtles imposed by boom deployment at a particular location. A spill at nesting or hatching time could have severe consequences to a turtle population. At other times, impacts might be minimal. In either case, 

consultation with resource experts and careful monitoring for turtle activity is advisable 

throughout a spill response in order to consider impacts of proposed response strategies 

on nesting and hatching events.

Offshore Dispersant Application 

Chemical dispersants contain surfactants that reduce the surface tension of oil, 

enabling the oil layer to be broken into fi ne droplets that mix into the water column and 

are dispersed by currents. Most oils will, to some degree, physically disperse naturally 

from agitation created by wave action and ocean turbulence; chemical dispersants are 

designed to enhance this natural process. Rapidly dispersing oil early in a spill reduces 

the oil on the water surface and thus the amount of oil available to be driven ashore 

by winds. In contrast, oil droplets dispersed in the water column are unlikely to strand 

ashore because they are driven by currents, not winds. An added benefi t of dispersing oil 

is that dispersants inhibit the formation of tarballs, a known hazard for turtles.

Dispersants are typically sprayed directly onto fl oating oil as fi ne droplets, either 

from aircraft or boats, generally within the fi rst several hours after a spill. Under appropriate conditions, lighter fuel to medium crude oils can be easily dispersed; heavier bunker 

oils much less so. Weathering increases oil viscosity and may cause formation of water-inoil emulsions, which are less amenable to dispersion. Among the advantages of dispersants are that they can treat large areas of spilled oil quickly and effectively before the 

slick can spread signifi cantly; can be applied in rougher weather and sea conditions than 

mechanical recovery methods; and can be used in areas too remote to deploy mechanical 

protection and cleanup methods.

Ideally, chemical dispersants should be applied in well-mixed waters, where the 

dispersed oil plume can be diluted to low levels before reaching productive nearshore 

waters. After dispersion into the water column, spreading or diluted oil becomes threedimensional, and concentrations drop rapidly. The highest concentration of chemically dispersed oil typically occurs in the top meter of water during the fi rst hour after 

treatment. Concentrations of more than 10 parts per million (ppm) of dispersed oil are 

unlikely below 10 m; even within 1 m, concentrations rarely exceed 100 ppm. The continuous mixing and dilution of open waters are suffi cient to rapidly reduce these concentrations; fi eld studies indicate that they decline to nearly undetectable or background 

levels within several hours of application. Dispersed oil droplets break down by natural 

processes such as biodegradation. The chemical dispersants applied, like the oil droplets, 

are diluted by diffusion and convective mixing, and readily biodegrade. Laboratory 

ppm - parts per 

million.
53

studies indicate that dispersed oil biodegrades much more rapidly than undispersed oil 

(within days to weeks).

Untreated surface oil can recoalesce in surface convergence zones even after it 

has spread to a very thin layer, and surfactants help to prevent this reoccurrence. Since 

juvenile turtles aggregate along convergence zones, using dispersants should reduce 

their exposure to oil. Dispersants also reduce adherence of oil droplets to solid particles 

and surfaces, and may reduce the tendency of oil to stick to turtle skin.

Unfortunately, little is known about the effects of dispersants on sea turtles, 

and such impacts are diffi cult to predict in the absence of direct testing. While inhaling 

petroleum vapors can irritate turtles’ lungs, dispersants can interfere with lung function 

through their surfactant (detergent) effect. Dispersant components absorbed through 

the lungs or gut may affect multiple organ systems, interfering with digestion, respiration, 

excretion, and/or salt-gland function—similar to the empirically demonstrated effects of 

oil alone. 

Although early dispersants contained components that were highly toxic to 

aquatic life, toxicity is signifi cantly reduced in modern formulations. For fi sh and other 

species that have been tested, dispersed oil is generally no more toxic than undispersed 

oil. Lutz created a very general framework for considering toxicity of oil dispersants to 

sea turtles (Figure 5.2) based on known effects of oil and hypothesized impacts of chemical dispersants, but direct experimental evidence to support the framework has not been 

generated.

Figure 5.2 Conceptual framework 

for considering chemical 

dispersant effects to sea turtles 

(adapted from Lutz 1989).

Dispersant

Lungs

Skin

Gut

Sense Organs

Permeability, Regeneration

Diffusion, Fluid balance

Digestion, Internal Effects

Interference

Route of exposure Potential Effect
54

As a general practice, surveying to ensure that no marine mammals or sea turtles 

are present can minimize the likelihood of direct contact with dispersant chemicals. 

Spraying might also be discouraged where turtles congregate, such as sargassum mats 

and convergence zones. But even with the disadvantages of dispersants, the consequences of sea turtles coming into contact with and ingesting fl oating oil (see Chapter 4) 

may argue for using their use to retard the formation of tarballs.

If applied appropriately offshore, chemical dispersants could be an effective tool 

for protecting turtles and the nearshore habitats they utilize. Possible effects on organisms in the water column and tradeoffs among resources at risk (such as coral reefs and 

seagrass beds) should be considered in spill response planning and decision-making.

Most regions that are home to turtle nesting sites and foraging areas have dispersant contingency plans in place. These plans have designated, specifi c pre-approval 

zones and guidelines for dispersant use, facilitating the decision-making process should a 

spill occur.4

Offshore In-situ Burning

In-situ burning is a response technique in which spilled oil is burned in place. 

Under appropriate conditions, in-situ burning can remove large quantities of oil quickly 

and effi ciently. Although this method has been effectively used for certain shoreline 

habitats (marshes, for example), consideration here is limited to using it on the open 

ocean.

In a typical in-situ burn in open, marine waters, oil is collected within a fi re-resistant, U-shaped boom, towed away from the main slick, and ignited. The boom is towed 

slowly to maintain the oil toward the back end—at the bottom of the U—and at a suffi cient thickness to sustain the burn. Most crude and refi ned oils will burn on water if the 

oil layer is at least a few millimeters (more than 2 to 3 mm) thick. The technique is less 

effective if winds are blowing harder than 20 knots and seas are higher than a half to 1 m, 

impeding the operator’s ability to control the boom and maintain the necessary oil thickness. In-situ burning can be used simultaneously with other oil spill response techniques 

or when other techniques are not feasible. The response window can last several days, 

although burn effi ciency is reduced by signifi cant emulsifi cation, evaporation of lighter 

and more easily burned volatiles, and spreading of spilled oil. Consequently, burning at 

sea is most effective early in a spill response.

A major potential advantage of in-situ burning is that it can remove large quantities (over 90 percent at maximum effi ciencies) of contained oil, potentially exceeding 

the maximum effi ciencies of mechanical and chemical response methods. Burning also 

requires less equipment and fewer personnel and produces less waste for disposal than 

other cleanup techniques. In remote areas and near sensitive habitats, where minimizing 
55

disturbance is desirable, in-situ burning can offer signifi cant logistical and environmental 

advantages.

Potential disadvantages of in-situ burning include production of highly visible 

smoke and other combustion by-products. Using this method in highly populated areas 

may be restricted due to concerns about the effect of fi ne particulate material in the 

smoke on human respiratory health. Special Monitoring of Applied Response Techniques 

(SMART) protocols were developed by the U.S. Environmental Protection Agency, the U.S. 

Coast Guard, NOAA, and the Agency for Toxic Substances and Disease Registry (ATSDR) to 

monitor particulate levels and provide real-time feedback to responders when burning is 

conducted near population centers. Such feedback helps responders determine levels at 

which smoke does not pose human health risks.

A practical limitation of burning is that the specialized boom that is used is 

expensive and not widely stockpiled around the coasts. Despite its limitations, the 

general consensus among researchers is that in-situ burning has a defi nite role in certain 

inshore situations (e.g., oil trapped in marshes), in ice, and where oil is being continuously 

released from a stationary source such as a well blowout (PMG, Inc. 2001).

Presumably, any in-situ burning would involve surveying the immediate area for 

turtles before proceeding. During a 1993 full-scale test of in-situ burning off the coast of 

Newfoundland, wildlife surveillance and hazing teams reportedly spotted a sea turtle in 

the test area prior to the burn ignition, but there was no indication of adverse effect to 

it or any other wildlife. Obviously, in-situ burning would be an unlikely response choice 

where sea turtles aggregate—although in such an area, the impacts of prolonged or 

heavy exposure to untreated surface oil would be evaluated against the risks. The ability 

of response crews to suffi ciently control and steer burning oil away from turtles in the 

water would be a major factor. Although a burn operation is fairly localized, whether sea 

turtles would avoid it is not known.

While the effects of smoke on sea turtles in particular have not been studied, 

at least one physiologist asserts that “lungs are lungs” and the effects should be similar 

for all air-breathing vertebrates. Evaluating human health risk from smoke plumes has 

focused on inhalation of very fi ne particulate material (termed PM10, or particulate 

material less than 10 microns in diameter) as the greatest risk factor. Fine particles can 

become lodged deep within the alveoli of the lungs, compromising respiratory capacity. 

Because turtles must surface regularly to breathe, they are at risk from inhaling gases and 

particulates present in a plume near the surface. Another hazard is that after a burn, a 

small percentage of the original oil volume remains as a taffy-like residue, which must be 

collected and disposed of properly. Since turtles are known to ingest tarballs and other 

solid materials they encounter, it is important that these residues be removed. In addition, under certain circumstances burned oil can sink, so operational personnel should 

evaluate the potential for burn residues to be denser than seawater. If this is likely to 

PM10 - particles 

with an aerodynamic 

diameter less than or 

equal to a nominal 10 

micrometers.

ATSDR - Agency for 

Toxic Substances and 

Disease Registry, U.S. 

Department of Health 

and Human Services.
56

happen near sea turtle habitat, in-situ burning would not be appropriate because sea 

turtles might try to eat the submerged oil residues.

Laboratory and fi eld studies of potential toxicity effects indicate situ burning 

does not have adverse effects on the underlying water column beyond those associated 

with unburned oil. Almost all heat is directed upward and outward, so heat absorbed 

by the underlying water is generally negligible, particularly where currents continuously 

exchange water beneath the burn.

Figure 5.3 portrays a decision fl owchart for in-situ burning that illustrates how 

wildlife considerations are factored into the overall framework for evaluating use of the 

technique.

Figure 5.3 Decision fl owchart for 

evaluating in-situ burning as 

a spill response option (adapted 

from U.S. Coast Guard and 

Environment Canada 1998).

Is there anything that can

be done to enhance burning

under these conditions?

Oil spill occurs

Find means other than

in-situ burning to deal with spill.

Is in-situ burning allowed

in this jurisdiction?

Are people living close

(<1 km) to the spill?

NO

YES

NO

YES

NO

YES

NO

YES

NO

NO

Does initial evaluation of the slick properties

indicate that in-situ burning would be

impossible under any conditions?

Are there animal or fish habitats

that could be affected by in-situ

burning?

Can this habitat be

protected by taking

precautionary measures?

Weather conditions during window

of opportunity: wind >40 knots,

wave height >2 m, or other conditions

unsuitable for burning?

YES

YES

YES

YES

NO

Expected oil properties during window

of opportunity: emulsification >50% and

stable, thickness <2–3 mm, or other property

that will prevent sustained burning

Is there any other reason why in-situ

burning should not take place or why

another response method would be

preferable to burning?

Begin the planning and preparation

process for in-situ burning.

YES

YES

NO

NO

NO
57

Shoreline Cleanup

Oil stranded on shorelines presents the greatest risk to sea turtles during the 

nesting season (Lutcavage et al. 1997). When oil comes ashore after nests have been dug 

and eggs laid, the response priority would be to protect the nests during cleanup and 

make every effort to remove oil from beaches and nearshore areas before eggs hatch 

and hatchlings head to sea (incubation is two months).

The general requirements for nesting beaches (Chapter 2) are that they be high 

enough to prevent tidal inundation, porous enough for gaseous exchange, and have 

moisture and sand grain characteristics that permit effective excavation. Depending 

on the specifi c situation and the time of year relative to nesting, many of the usual 

and accustomed shoreline cleanup methods appropriate for sand beaches may be 

employed—but with additional caveats. Manual methods, mechanical cleanup (with 

some constraints), use of sorbents, sediment reworking, and vacuum techniques have all 

been successfully used to collect and/or reduce the degree of oiling on sand beaches. 

Oiled wrack or debris could also be collected and disposed—although this would need 

to be balanced against the increased foot traffi c and potential for disturbance.

Passive Methods

Passive response methods rely on some mechanism to collect and hold 

oil until workers can remove it for disposal. The most common are absorbents 

and adsorbent booms and pads, which act as sponges to bind and channel 

oil. Adsorbent equipment, primarily “pom-poms” or snare booms, bind oil 

to exterior surfaces of oil-attracting (oleophilic) material (Figure 5.4). Either 

approach requires tending to ensure proper deployment and replacement 

when saturated with oil.

Manual and Mechanical Oil Removal

Both manual and mechanical removal methods work well on sand beaches, 

and both have been used at turtle nesting sites. Manual removal is preferred because it 

requires less heavy equipment and tends to remove less sand. Sand removal should be 

minimized as much as possible on turtle nesting beaches, and beach profi les should not 

be altered because female turtles coming ashore to dig nests could become disoriented. 

However, if oiling is extensive and subsurface oiling is present, mechanical methods can 

be used with some precautions and careful oversight. A combination of mechanical and 

manual removal methods were used at spills in Tampa Bay and Puerto Rico (see pages 76 

and 78). Oleophilic - 

oil-attracting.

Figure 5.4 A sea turtle nest 

endangered by the 1993 

Bouchard B155 oil spill in 

Tampa Bay. The trench and 

adsorbent snare boom (black 

material on the ocean-facing 

side of the nest) are intended to 

reduce the severity of exposure 

from any oil stranding near the 

nests. Photo courtesy of Dr. Anne 

Meylan, Florida Fish and Wildlife 

Conservation Commission, 

Florida Marine Research Institute.
58

Disposing of oiled sand is an important aspect of manual or mechanical removal, 

because it involves transporting potentially large quantities of material to treatment or 

disposal sites. Offsite treatment, and later replenishment, is an alternative that can be 

considered, especially where sand is not naturally replenished on beaches. At the Berman

barge spill in Puerto Rico, oiled sand was treated off-site; however, the cleaned sand was 

not redeposited on the beach. Instead it was used for construction projects. 

Turtle nests should not be disturbed during cleanup activities. This guidance 

is complicated by the fact that, in most cases, when oil is threatening a nesting beach 

during nesting season, the majority of sea turtle nests will be unmarked. If nesting locations are known, they can be protected by controlling access routes to the beach, marking and fencing sites, and carefully deploying equipment and personnel. It is unlikely 

that turtle nests would be directly impacted if shorelines were oiled after eggs had been 

deposited, since females typically dig nests well above the high-tide line. However, survey 

and response workers could conceivably crush eggs, and sand could be compacted over 

nests, which would make it diffi cult for hatchlings to emerge. At the barge Bouchard B155

spill in Tampa Bay (page 76), the relatively small number of turtle nests on area beaches 

made it possible for volunteers to clearly mark nest locations and protect them with a 

fence. Hatchlings were collected, transported south to another county, and released (A. 

Meylan 20025

). Mechanical cleanup methods were used extensively at this spill, largely 

because of the challenge of removing thick layers of buried oil. However, response 

vehicles were restricted to the middle and lower intertidal levels, well away from nesting 

sites.

Generally, fencing and marking nests after a spill, or when a threat exists, works 

only for the most recent nests, not for those that have been in the ground for a longer 

time. Figure 5.4 illustrates some important aspects of the approach resource managers used during the Bouchard B155 spill: the nest is conspicuously marked (not simply a 

stake), and it encloses a large area that includes a buffer. The buffer area was a critical 

protective zone when the beach was worked by heavy equipment (A. Meylan 20026

).

Bioremediation

Bioremediation, specifi cally adding nutrients to a spill area, can speed oil degradation in many habitats, including sandy beaches (Venosa et al. 1996). A major limitation 

of bioremediation at turtle nesting beaches is that it takes at least several weeks before 

oil is successfully degraded to background levels. Time is often critical when cleaning oil 

in turtle habitats. If oiling occurs when no turtles are present or expected within approximately six weeks, then nutrients could be added after the major portion of the oil has 

been removed by other methods.

One approach considered to be a bioremediation technique on sand beaches is 

tilling, in which the beach surface is worked with equipment to expose and aerate oil resi-
59

dues. Although tilling is frequently used on recreational beaches (it resembles grooming 

practices common in such areas), it is not recommended on nesting beaches because it 

would be disruptive.

Vacuuming 

Vacuuming can remove pooled oil or thick oil accumulations from the sediment 

surface, depressions, and channels. Vacuum equipment ranges from small units to large 

suction devices mounted on dredges or trucks. Vacuuming can be used effectively on 

heavier and medium oils, provided they are still reasonably fl uid. Lighter, more fl ammable petroleum products, such as jet fuel and diesel, generally should not be vacuumed.

Indirect Response Impacts

Unintended adverse impacts to turtles may be caused by response activities, and 

should be anticipated and controlled. Examples include:

· Foot and equipment traffi c in nesting areas. Compressing sand in the upper 

intertidal and dune areas should be avoided because compression makes it more 

diffi cult for females to dig nests and for hatchlings to dig themselves out. Equipment 

and personnel also can crush eggs in nests. Vibrations from heavy machinery may 

result in hatchlings emerging from their nests during the day, timing that would 

leave them more vulnerable to predators (S. Milton 20027).

· Artifi cial light. Any artifi cial lighting associated with the response should be 

minimized during the nesting season, because females and hatchlings, which are 

attracted to bright light, are easily disoriented by artifi cial lighting. Turtle researchers 

try to minimize even the use of fl ashlights at night. Witherington and Martin (2000) 

provide extensive, detailed information and guidance on lighting considerations that 

affect sea turtle behavior. This would prove to be a practical and relevant reference 

during a major spill response in which beach activity could take place at night.

· Artifi cial barriers on the beach, including berms, sorbents, and booms can prevent 

hatchlings from reaching the water and adult females from reaching potential 

nesting sites. For hatchlings, temporary entrapment by a boom can increase the risk 

of predation during their migration to the water, when they are especially vulnerable 

to predators.

· Small boat traffi c and increased collision risk. Boat operators working in offshore 

shallow areas need to be cognizant of the risk of colliding with swimming turtles and 

take precautionary measures.
60

Preventative Measures

A potential worst-case scenario was faced during the Ixtoc I well blowout in 1979, 

when the only nesting site of the Kemp’s ridley turtle was threatened by oil during the 

nesting season. When there seems to be no other option, or if a large percentage of an 

entire species’ population may be at risk from oiling, nests may need to be relocated or 

hatchlings captured and released at a location free of oil.

Relocating Nests

Relocating sea turtle eggs should only be undertaken when other alternatives 

are not available. Nests should be relocated only within 12 hours of egg deposition, after 

which moving an egg is likely to disturb the newly attached egg membranes and kill the 

embryo. Eggs may also be moved after 14 days of incubation (Limpus et al. 1979). The 

eggs should be handled gently and any unnecessary movement (especially rotation) 

avoided. If relocation is adopted as an option during a spill, only trained, experienced, and 

authorized personnel may disturb nests or move eggs. In addition, specifi c permits from 

state and federal regulators will likely be necessary for specialists handling turtles and 

turtle nests.

Capture and Release of Hatchlings

Another mitigation technique is to leave the eggs to hatch naturally from their 

nests, but to capture the turtle hatchlings before they migrate to the water. Hatchlings 

are then released at an alternative location, free of oil. This technique was used for Kemp’s 

ridley hatchlings during the Ixtoc I spill (described in greater detail on page 73).

Application of Sea Turtle Information for Spill Response and Planning

Since we already know that it is a good idea to prevent sea turtles from coming 

into contact with oil, fi nding operational and practical spill response information is 

important in any response planning. An initial question asked at any incident is, “What 

is at risk?” For turtles, a spill response tool developed and supported by NOAA is the 

Environmental Sensitivity Index (ESI) atlases, which portray geomorphology (shoreline 

characteristics) and resource information for an area. Turtles are a major feature of 

Florida’s ESI maps, which depict nesting beaches, in-water distribution, shoreline habitats, 

species composition, seasonality, relative concentration, nesting beach survey boundaries, 

and source documentation (Zengel et al. 1998). Much of the information was provided by 

state biologists and resource managers. Figure 5.5 is an example of the resultant product.

ESI - Environmental 

Sensitivity Index map.
61

Figure 5.5 An Environmental 

Sensitivity Index map for South 

Florida’s turtle habitat areas.
62

In other U.S. waters, there is enough basic information about nesting patterns 

that can be consolidated into a quick graphic reference that shows which turtles might 

be at risk at a given time of day and year from an oil or hazardous chemical release and 

subsequent response to it. Figure 5.6 shows that the middle of the year—from around 

March through September—is when oil spilled on or near nesting beaches would likely 

result in the greatest exposure to turtles. Conversely, December through February is a 

period of low activity near the beaches themselves. The fi gure also shows the generally 

observed day and night timing patterns for nesting across species; that is, which species 

typically come ashore at night and which ones come ashore during the day. As might 

be expected, this graphic comes with a qualifi er; it should be used as a general reference 

only, and local biological experts should always be consulted as the primary source of 

information.

In the United States, the state of Florida has been most active in attempting to provide a standardized approach to interactions with sea turtles and sea 

turtle nests. Florida has developed comprehensive guidelines for dealing with sea 

turtles on state beaches. Excerpts from a single section of Florida’s “Marine Turtle 

Guidelines” are included as Appendix B. The full document is available online at 

http://fl oridaconservation.org/psm/turtles/Guidelines/MarineTurtleGuidelines.htm.

Appendix B includes only the material that might be instructive for spill response 

and shoreline survey activities, nesting surveys, and identifi cation of nesting sites. The 

guidelines describe appropriate ways to identify and mark nesting sites, which might 

Figure 5.6 Times when oil near 

or on nesting beaches will have 

the most and least effect on 

turtles, by species. From Miller 

(1997) and U.S. Fish and 

Wildlife Service (2003).

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Green

Hawksbill

Leatherback

Loggerhead

Kemp's ridley

Olive ridley

Key: Predominant nighttime nesters Predominant daytime nesters Day and night nesters
63

be adapted for use during oil spill responses. While a spill responder needs to have a 

complete understanding of how various spill containment and cleanup operations may 

affect sea turtles in the water and on the nesting beach, he or she does not need to have 

the sort of training that permit holders possess to handle marine turtles, hatchlings, and 

nests. Florida permit holders have this information already, and other states may have 

different requirements. As previously noted, anyone engaging in these direct activities 

with sea turtles would need to be properly permitted and possess this expertise and 

training.

Readers are encouraged to view the complete Florida guidelines to more fully 

understand the complexities of managing turtles in close proximity to human populations. While they are specifi c to Florida (other jurisdictions will have different or perhaps 

confl icting policies for dealing with turtle issues), they are nevertheless relevant and 

usable for spill responders in the fi eld.

During a Fort Lauderdale oil spill of undetermined origin in 2000 (see page 

79), both the U.S. Fish and Wildlife Service (USFWS) and the Florida Fish and Wildlife 

Conservation Commission sea turtle staff were asked to provide general guidance on 

how to minimize impacts to sea turtles. The following simple guidelines were provided 

(S. MacPherson 20028

):

· Daily early morning nesting surveys should be completed prior to any heavy 

equipment being allowed on the beach.

· Nests should be marked for avoidance by heavy equipment.

· Hatchlings emerging from nests in an area where oil is present on the beach and/or 

in the adjacent offshore area should be collected and released on a non-impacted 

beach.

· If oiled turtles start washing ashore, stranding surveys may need to be increased to 

more than once per day.

Handling and Rehabilitation

Beyond the observation that turtles are seriously harmed by oil contact, we know 

very little about actual cause-and-effect relationships related to sea turtle oil exposure. 

Not knowing what physiological systems are most vulnerable, it is not possible to recommend precise rehabilitation measures, except those related to salt gland function 

(detailed below). Otherwise, little fi rm information is available on which to base rehabilitation best management practices during an oil spill. As a result, well-intentioned but 

questionable ad hoc rehabilitation efforts have been documented: for example, in 1990, a 

young hawksbill turtle covered with crude oil was found off Kralendijk, Bonaire, and taken 

to a mariculture facility, where it was cleaned with kerosene and detergent (Sybesma 

1992).
64

While not necessarily oil-specifi c, there are, however, well-established procedures 

in many areas of the United States for dealing with stranded sea turtles , defi ned as 

those that wash ashore either dead or alive. A national Sea Turtle Stranding and Salvage 

Network (STSSN), established in 1980, provides protocols for documenting and handling 

stranded animals (Shaver and Teas 1999). In the event of an oil spill where sea turtles 

could be affected, state coordinators for the STSSN (where designated) should be contacted, and shoreline assessment activities should be coordinated with these trained and 

permitted experts. Appendix C is a list of current STSSN coordinators for the Atlantic and 

Gulf coasts.

Some guidance for handling sea turtles during spills does exist and is included 

below as reference material and to serve as a possible basis for action. Appendix A, the 

at-sea handling protocol prepared by Dr. Anne Meylan of the Florida Marine Research 

Institute, is one example. The protocol was created during the 1993 Bouchard B155 barge 

spill in case large numbers of turtles were encountered during the response and cleanup. 

Although they are simple, common sense guidelines, they provide a consistent and standardized framework for dealing with sea turtles and are a useful addition to spill response 

guidance in a specifi c setting.

Another example, which would be applied under the auspices of trained wildlife 

veterinarians and resource managers, is more narrowly focused on treatment and monitoring of oiled sea turtles in a rehabilitation center. Walsh (1999) provides an excellent 

overview of general rehabilitation practices for sea turtles, and other experienced wildlife 

veterinarians and physiologists (e.g., Bossart 19949

; Mignucci-Giannoni 1999) have provided insights that might be incorporated into standard operating procedures during 

cleaning and rehabilitation activities for a given spill. Some procedures are shared with 

bird-cleaning protocols; others have been found to work well with turtles in particular. 

The guidelines are:

· Remove surface oiling

 . . . dishwashing detergent (e.g., Dawn®) or other mild surfactants have been used, 

along with copious amounts of warm water (Walsh 1999).

 . . . food oils, such as olive, sunfl ower, or soy, have been found to be effective in 

breaking up and removing external oiling (Mignucci-Giannoni 1999; Levy 200210)

· Rinse and dry

· Repeat cleaning

 . . . 24 to 48 hours later dependent on health status (cleaning cycle repeated until all 

physical oiling removed (Mignucci-Giannoni 1999)

· Clean head and oral cavities

 . . . (cloths dampened with food oil)

· Administer organic fats (mayonnaise)

STSSN - Sea Turtle 

Stranding and Salvage 

Network.
65

 . . . via force-feeding tube (Walsh 1999; Levy 2002; Schaf 200211) to facilitate clearance 

of oil or tar fouling in the esophagus and gastrointestinal tract.

· Orally administer material to coat gastrointestinal lining

 . . . and provide relief from irritation (olive oil or Pepto-Bismol®) (Mignucci-Giannoni 

1999; Bossart 199412)

 . . . if ingestion is suspected, charcoal-containing compounds may decrease 

absorption of hydrocarbons that can cause organ damage (Walsh 1999)

· Support with fl uids

 . . .(interperitoneal if necessary)

· Monitor output of tears

 . . . (secretions) from salt glands (see discussion below)

· Reassess health status daily

 . . . serial blood samples can help to direct therapy (Walsh 1999)

 . . . consider euthanasia for very poor condition animals (USFWS permits required)

Observations in the sea turtle oiling experiments conducted by Lutcavage et al. 

(1995) (Chapter 4) and at the 1993 Tampa Bay spill suggest that oil exposure can cause 

turtle salt glands to effectively shut down, at least temporarily. In the Tampa Bay incident, 

this phenomenon was observed in sea turtles that were cleaned prior to release. Because 

the salt gland function appears to return to normal slowly, Lutcavage (199413) and Lutz 

(200214) recommend holding rehabilitated animals for at least 10 to 14 days in isosmotic, 

one-third seawater and monitoring the osmolarity of salt gland output by collecting and 

measuring tear salinity with an osmometer.

As noted in Chapter 2, the sea turtle salt gland is not always turned “on;” that is, 

it must be stimulated by exposure to a salt load. Differences in osmolarity of secretions 

are substantial between inactive and active salt glands. Lutz (1996) summarized results 

from several studies to show that the scant secretions from inactive salt glands measure 

around 300 to 400 milliosmol/kg (about equal to turtle plasma), while stimulated salt 

gland secretions average around 1,900 milliosmol/kg, about twice the salinity of seawater. Lutz noted that the osmolarity for salt gland secretions from two species, greens and 

loggerheads, were nearly equal: 1,900 and 1,854 milliosmol/kg. In a spill rehabilitation 

setting, veterinary staff should, at a minimum, ensure proper function of salt glands 

before releasing individuals back to the wild, because animals may be imperiled if 

released prematurely (M. Lutcavage15).

Finally, for veterinary professionals dealing with the basics of sea turtle care and 

rehabilitation, a recently published NOAA technical memorandum, “The Anatomy of Sea 

Turtles” (Wyneken 2001) is a key reference document. This profusely illustrated, in-depth 

technical document should be considered as a remarkable and necessary resource for 

Osmolarity - 

the concentration 

of an osmotic solution, especially when 

measured in osmols or 

milliosmols per liter of 

solution.

Figure 5.7 An oiled green turtle 

recovered by the Israeli Sea Turtle 

Rescue Center in August 1999. 

This and another individual 

were cleaned, rehabilitated, 

and released about two months 

later. The source of oiling was 

not identifi ed. Photo courtesy 

of Yaniv Levy, Israeli Sea Turtle 

Rescue Center, Hofi t, Israel.
66

those involved in veterinary medicine related to sea turtles. It is currently available in 

three forms: print, CD-ROM, and online in pdf format at http://courses.science.fau.edu/

~jwyneken/sta/).

For Further Reading

Allen, A. A., and R. J. Ferek. 1993. Advantages and disadvantages of burning spilled oil. In: Proceedings of the 

1993 International Oil Spill Conference, March 29–April 1, 1993, Tampa, Fla. pp. 765–772.

American Petroleum Institute (API), National Oceanic and Atmospheric Administration, U.S. Coast Guard, and 

U.S. Environmental Protection Agency. 2001. Characteristics of Response Strategies: A Guide for Spill Response 

Planning in Marine Environments. API, Washington, D.C. 78 p.

Caribbean Regional Response Team. 1995. Dispersant Usage Plan. In: Use of dispersants in the Caribbean. 

Prepared for Caribbean Regional Response Team, Response and Technology Committee, Dispersant 

Workgroup, San Juan, Puerto Rico. 71 p.

Daykin, M., G. Sergy, D. Aurand, G. Shigenaka, Z. Wang, and A. Tang. Aquatic toxicity resulting from in-situ

burning of oil-on-water. In: Proceedings of the Seventeenth Arctic and Marine Oil Spill Program (AMOP) Technical 

Seminar, June 8–10, 1994, Vancouver, B.C., Environment Canada, Ottawa, Canada. 2: 1165–1193.

Fingas, M. F., F. Ackerman, K. Li, P. Lambert, Z. Wang, M. C. Bissonnette, P. R. Campagna, P. Boileau, N. Laroche, P. 

Jokuty, R. Nelson, R. D. Turpin, M. J. Trespalacios, G. Halley, J. Belanger, J. Pare, N. Vanderkooy, E. J. Tennyson, D. 

Aurand, and R. Hiltabrand. 1994. The Newfoundland Offshore Burn Experiment—NOBE: Preliminary results of 

emissions measurement. In: Proceedings of the Seventeenth Arctic and Marine Oil Spill Program (AMOP) Technical 

Seminar, June 8–10, 1994, Vancouver, B.C., Environment Canada, Ottawa, Canada. 2: 1099–1164.

Fingas, M. F., G. Halley, F. Ackerman, N. Vanderkooy, R. Nelson, M. C. Bissonnette, N. Laroche, P. Lambert, P. Jokuty, 

K. Li, G. Halley, G. Warbanski, P. R. Campagna, R. D. Turpin, M. J. Trespalacios, D. Dickens, E. J. Tennyson, D. Aurand, 

and R. Hiltabrand. 1994. The Newfoundland Offshore Burn Experiment—NOBE: Experimental design and 

overview. In: Proceedings of the Seventeenth Arctic and Marine Oil Spill Program (AMOP) Technical Seminar, June 

8–10, 1994, Vancouver, B.C. 2: 1053–1163.

Fingas, M. F., and M. Punt. 2000. In-situ burning: A cleanup technique for oil spills on water. Emergencies 

Science Division, Environmental Technology Centre, Environment Canada, Ottawa, Ont. 214 p. 

Fritts, T. H. and M. A. McGehee. 1982. Effects of petroleum on the development and survival of marine turtle 

embryos, U.S. Fish and Wildlife Service, U.S. Department of the Interior, Washington, D.C., Contract No. 14-16-

0009-80-946, FWS/OBS-82/37.

International Maritime Organization (IMO). 1997. Field Guide for Oil Spill Response in Tropical Waters. IMO, 

London. 54 p. 

Limpus, C. J., V. Baker, and J. D. Miller. 1979. Movement induced mortality of loggerhead eggs. Herpetologica

35: 335.

Lutcavage, M. E., P. L. Lutz, G. D. Bossart, and D. M. Hudson. 1995. Physiologic and clinicopathologic effects of 

crude oil on loggerhead sea turtles. Arch. Environ. Contam. Toxicol. 28: 417–422.

Lutz, P. L. 1989. Methods for determining the toxicity of oil and dispersants to sea turtles. In: Oil and Dispersant 

Toxicity Testing: Proceedings of a Workshop on Technical Specifi cations Held in New Orleans, T. W. Duke and G. 

Petrazzuolo, eds. Prepared under MMS contract 14-12-0001-30447, OCS Study MMS 89-0042, pp. 97–101.

Lutz, P. L. 1997. Salt, water, and pH balance in the sea turtle. In: The Biology of Sea Turtles, Vol. I, P. L. Lutz and J. A. 

Musick, eds. CRC Press, Boca Raton, Fla. pp. 343–361.

Mignucci-Giannoni, A. A. 1999. Assessment and rehabilitation of wildlife affected by an oil spill in Puerto Rico. 

Environ. Pollution 104(2): 323–333.
67

Miller, J. D. 1997. Reproduction in sea turtles. In: The Biology of Sea Turtles, Vol. I, P. L. Lutz and J. A. Musick, eds. 

CRC Press, Boca Raton, Fla. pp. 51–81.

NOAA, Hazardous Materials Response and Assessment Division. 1993. Shoreline countermeasures manual: 

Tropical coastal environments. NTIS PB94-160926. Hazardous Materials Response & Assessment Division, 

NOAA, Seattle, Washington. May. 80 p. + appendices.

Potomac Management Group, Inc. 2001. Risk assessment for the Coast Guard’s Oil Spill Prevention, 

Preparedness and Response (OSPR) Program: Phase I—concept development, risk characterization and 

issue identifi cation. Prepared for U.S. Coast Guard Offi ce of Response (G-MOR) under Contract # DTCG23-00-

MM3A01.

Sybesma, J. 1992. WIDECAST sea turtle recovery action plan for the Netherlands Antilles, K. L. Eckert, ed. CEP 

Technical Report No. 11, UNEP Caribbean Environment Programme, Kingston, Jamaica. 63 p.

U.S. Coast Guard. 2002. Inter-agency Memorandum of Agreement regarding oil spill planning and response 

activities under the Federal Water Pollution Control Act’s National Oil and Hazardous Substances Pollution 

Contingency Plan and the Endangered Species Act. A guidebook, version 2002. United States Coast Guard, 

Washington, D.C.

U.S. Coast Guard and Environment Canada. 1998. In-situ burning of oil slicks on water—procedures and 

techniques. Draft report. United States Coast Guard, Washington, D.C.

U.S. Fish and Wildlife Service. 2003. Data from web site: http://northfl orida.fws.gov/seaturtles/turtle-factsindex.htm.

Venosa, A. D., M. T. Suidan, B. A. Wrenn, K. L. Strohmeier, J. R. Haines, B. L. Eberhart, D. King, and E. Holder. 1996. 

Bioremediation of an experimental oil spill on the shoreline of Delaware Bay. Environ. Sci. and Technol. 30: 

1764–1775.

Walsh, M. 1999. Rehabilitation of sea turtles. In: Research and Management Techniques for the Conservation of 

Sea Turtles. IUCN/SSC Marine Turtle Specialist Group Publication No. 4, pp. 202–207.

Witherington, B. E., and R. E. Martin. 2000. Understanding, assessing, and resolving light-pollution problems on 

sea turtle nesting beaches. Technical Report TR-2, Second Edition, Revised, Florida Marine Research Institute, 

St. Petersburg, Fla. 73 p.

Wyneken, J. 2001. The anatomy of sea turtles. NOAA Technical Memorandum NMFS-SEFSC-470, Miami, Fla. 

172 p.

Zengel, S., A. Meylan, H. Norris, M. White, L. Diveley, W. Holton, and K. Moody. 1998. Mapping sensitive sea turtle 

areas in Florida for oil spill response and natural resources management. In: Proceedings of the 16th Annual 

Symposium on Sea Turtle Biology and Conservation, R. Byles and Y. Fernandez, compilers. NOAA Technical 

Memorandum NMFS-SEFSC-412, Miami, Fla. pp. 156–157.

Chapter Notes

1

 L. Herbst, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, personal communication.

2

 See, for example, Characteristics of Response Strategies: A Guide for Spill Response Planning in Marine 

Environments (American Petroleum Institute et al., 2001) for an overview of typical response options for 

several habitats.

3

 Detailed descriptions of the various containment and collection techniques and equipment can be found 

in the comprehensive Field Guide for Oil Spill Response in Tropical Waters, available from the International 

Maritime Organization (IMO).

4

 See, for example, the Caribbean Regional Response Team Dispersant Usage Plan (CRRT 1995). See p. 66.
68

5

 A. Meylan, Florida Fish and Wildlife Conservation Commission, Florida Marine Research Institute, 100 Eighth 

Avenue SE, St. Petersburg, FL 33701-5095, personal communication, 2002.

6 A. Meylan, Florida Fish and Wildlife Conservation Commission, Florida Marine Research Institute, 100 Eighth 

Avenue SE, St. Petersburg, FL 33701-5095, personal communication, 2002.

7

 S. Milton, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991, personal communication, 

2002.

8

 S. MacPherson, U.S. Fish and Wildlife Service, 6620 Southpoint Drive South, Suite 310, Jacksonville, FL 32216, 

personal communication, 2002.

9 G. Bossart, Harbor Branch Oceanographic Institution, Ft. Pierce, FL 34946, personal communication, 1994.

10 Yaniv Levy, Israeli Sea Turtle Rescue Center, Hofi t, Israel, personal communication, 2002.

11 S. Schaf, The Turtle Hospital, Marathon, FL 33050, personal communication, 2002.

12 G. Bossart, Harbor Branch Oceanographic Institution, Ft. Pierce, FL 34946, personal communication, 1994.

13 M. Lutcavage, Edgerton Research Laboratory, New England Aquarium, Central Wharf, Boston, MA 02110, 

personal communication, 1994.

14 P. Lutz, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991, personal communication, 

2002.

15 M. Lutcavage, Edgerton Research Laboratory, New England Aquarium, Central Wharf, Boston, MA 02110, 

personal communication, 1994.
69

Chapter 6 Case Studies of Spills that Threaten Sea 

Turtles

Ruth A. Yender and Alan J. Mearns

Key Points 

· Sea turtles have been at risk of exposure in many oil spills, particularly in the 

Caribbean and Gulf of Mexico.

· There are surprisingly few reports of sea turtles or their nest sites being oiled or 

injured during the response to an oil spill.

· In recent years the typical incident threatening sea turtles is not from crude oil from 

a tanker, but rather from a fuel oil spill from grounded fi shing vessels or cargo ships.

· Despite the potential for oil spills to harm sea turtles, actual incidents in which 

impacts have been documented are rare.

· Absence of documentation does not imply absence of effect, but is due to the low 

probability of observing and recovering oiled turtles.

· Most reports of sea turtle impacts are from Florida or the Caribbean.

Past and Present Spills that Threaten Sea Turtles 

Planning response activities for spills that threaten sea turtles may be improved 

by understanding past spills and response to them. How many incidents occurred that 

threatened sea turtles? What kinds of accidents were most threatening? What products 

were involved? How many turtles were exposed, threatened, or affected? How did the 

response minimize injury to sea turtles? By studying and understanding the answers to 

these questions and considering them “lessons learned,” we can improve preparedness 

and response methods for spills affecting sea turtle habitats.

To answer these questions, NOAA HAZMAT reviewed two sources of data and 

information on past spills and incidents in ocean areas occupied by sea turtles (accessible on the NOAA HAZMAT website at http://response.restoration.noaa.gov), along with 

three international case histories that occurred in recent years, but which are not in these 

databases.

1. The NOAA HAZMAT Historical Incidents Database contains reports and images from 

about 1,000 oil spills and chemical accidents from 1977 to 2001. It includes mostly 

U.S. incidents, some signifi cant international incidents, and incidents in which a spill 

was averted (no oil spilled), but which at the time posed a threat. It does not include 

inland events that occurred away from the coast or navigable waterways.

HAZMAT - 

NOAA Hazardous 

Materials Response 

Division
70

2. The 1992 NOAA HAZMAT Case History document includes information on 110 

“signifi cant” spills that occurred worldwide between 1967 and 1991. To these we 

added three additional international case histories that occurred in recent years, 

but which are not in these databases. Case histories summarized in this chapter are 

ones that exceeded 4 million gallons (gal) total (419,000 gal in U.S. waters); involved 

the use of dispersants; involved bioremediation; or involved severe environmental 

impacts (more than 500 birds and 100 mammals killed, over a mile of intertidal zone 

smothered, fi sheries closed, etc.).

Both information sources were searched for spills that may have threatened sea 

turtles or their nesting sites and habitat. A word of caution. First, the information is not 

comprehensive, that is, not all spills and potential spills were reported. Therefore, interpretation of trends and frequencies need to be taken with a grain of salt. Second, these 

are mainly response reports and may not contain additional follow-up information, such 

as that appearing in the literature or in government or industry damage assessment and 

restoration reports many years after the initial spill response.

The Big Picture: 1967–2001

The years 1967 to 2001 included 126 incidents. Despite a long history of major 

oil spills, the case history fi les indicate that few incidents reported oiling, contaminating, 

or killing of sea turtles or oiling of nesting sites. Either turtles were rarely impacted or the 

historical fi les are not suffi ciently complete or detailed to document injuries, protection 

strategies, or rehabilitations.

Number of Incidents

Of the incidents documented,104 mentioned sea turtles, and 91 incident reports 

suggest marine turtles may have been at risk. Oil or fuel actually spilled in only 67 of the 

91 cases. Of these, oiled, injured, or dead sea turtles were reported in only seven cases: 

Witwater, Alvenus, Trague Beach (Guam), Gulf War, Vista Bella, Barge Bouchard, and Barge 

Morris J. Berman. 

Locations of Spills

Of 110 incidents reported in the1992 NOAA HAZMAT Case History Report, 43 

occurred in tropical and subtropical waters, approximately 30° N to 30° S, half of which 

were also reported in the historical incidents database. Only four (Alvenus, Peck Slip, 

St. Peter, and Virgin Islands Water and Power), explicitly listed turtles or nesting sites as 

resources at risk.
71

Volume Spilled 

About 770 million gal of oil and fuel were spilled, most of it by the three largest 

and longest marine spills in history: 

· the 1991 Gulf War spill in Kuwait and Saudi Arabia (252 million to 335 million gal);

· the 1979 Ixtoc I platform blowout in Campeche Bay, Gulf of Mexico, (147 million gal); 

and

· the 1983 Norwuz spill in the Arabian Gulf (79 million gal).1

Median volume of all tropical spills from 1967 to 2001 was 38,900 gal. Excluding 

the three mega-spills, the median volume was relatively unchanged (34,985 gal). From 

the 1960s through the 1980s, most larger oil spills were from shore facilities, damaged 

tankers, and oil platform accidents. Several nearshore spills resulted from vessel groundings.

Materials Spilled

Many potential or actual incidents involved two or more oil products. Of 121 

separate (specifi c) products, only 42 (35 percent) were crude oils; the remaining 79 

products (65 percent) were fuels, lube oils, and other refi ned products.

Response Methods

Responses mainly involved conventional methods for protection (booming) 

and removal (skimming, shoreline cleanup). Dispersants were used or considered on 34 

spills—some successfully, others with little or no success. Most dispersants were used 

on international (non-U.S.) spills, but seven were in Puerto Rico, four in Texas, three in 

Louisiana, and one in New Jersey. There is no information about the extent to which oil 

or dispersants affected sea turtles.

The Past Decade (1992–2001) 

Large crude oil spills decreased in frequency and volume in the last decade (NRC 

2002). Seventy-three actual or potential spills occurred in tropical areas or at times when 

turtles were indicated as resources at risk.

Spill Locations

Geographically, most incidents occurred along the Gulf of Mexico (26) and 

Florida’s Atlantic coast (9). Another 16 occured in the Caribbean (13 in Puerto Rico alone), 

12 in Atlantic states north of Florida, 9 in the Pacifi c, and 1 in South America. Of these 73 

cases: 

· Sea turtles and their nest sites or habitats were noted at risk during response in 40 

(55 percent) cases. 
72

· Only three (4 percent) occurred where turtles or nest sites were noted as oiled or 

otherwise protected or rehabilitated.

· Fifty-two (71 percent) resulted in actual spills.

· Fifty-four incidents (74 percent) were from vessels; 13 (18 percent) were from 

pipelines, platforms, or docks.

Volume Spilled

The total volume spilled was 3.3 million gal: 2.5 

million gal from vessels and 738,400 gal from stationary 

sources. The median incident release (including averted 

spills) was only about 3000 gal, a ten-fold decrease from 

the medians in the 34 years from 1967 through 2001. 

The median volume from mobile sources was 4,032 gal, 

ranging from 126 to 287,185 gal; from stationary 

sources, the median was 12,600 gal, ranging from 42 to 

284,465 gal.

Sources

Among the mobile sources (Figure 6.1), 23 (43 

percent) were from freighters (carriers), 12 (22 percent) 

from barges, 9 (17 percent) from fi shing boats, and 5 (9 

percent) from tugboats. Only 3 incidents (6 percent) 

involved tankers. Among stationary sources, 6 spills (46 

percent) were from pipeline breaks, and 4 (31 percent) 

were from storage facilities.

Material Spilled

As shown in Figure 6.2, the most frequent material was diesel or No. 2 fuel oil (34 cases), followed by No. 

6 fuel (15), intermediate fuel oils (12), lube oil (11), Bunker 

C (9), crude oil (9), other refi ned products (8), and jet fuel 

(3). Thus most spills threatening turtles during the past 

decade involved refi ned products (89 percent), not crude 

oil. Twenty of the 54 incidents spilled more than one 

product for a total of 101 product spills. 

Cause of Spills

Fifty-four spills were from mobile sources (vessels), 13 from stationary sources, 

and 6 from other sources.

Figure 6.1 Sources of oil spilled in 

tropical areas, 1992–2001.

Figure 6.3 Causes of incidents in 

tropical areas, 1992–2001.

Figure 6.2 Types of oil and fuels 

spilled in tropical incidents, 

1992–2001.

12

23

2 9

5

3

6

4

4

5 Barge

Carrier/Freighter

Cruise ship Fishing vessel

Tug

Oil Tanker

Pipeline

Storage facility

Miscellaneous

Mystery spill

34

15

9

12

11

3

8

9

No. 2/diesel

No. 6

Bunker

IFO

Lube oil

Jet

Other

Crude

32

4

4

4

2

1 4

1

2

Grounding

Collision (Structure)

Dock Accident

Sinking

Fire

Old wreck

Collision

Lightering Sinking
73

Of the spills from mobile sources (Figure 6.3), 32 (60 percent) were from vessel 

groundings, and the rest from collisions, dock accidents, sinkings, fi res, and lightering. Of 

all spills in tropical waters between 1992 and 2001, most (85 percent) occurred from the 

shoreline or very close to shore.

Response Methods

Responses to most spills involved traditional methods of containment (boom) 

and removal (skimming, shoreline cleanup). Dispersants were used or considered on 12 

spills; spills were averted in 3 incidents. Three dispersed spills occurred in Puerto Rico, 2 

in Texas, and 1 each occurred at St. Eustatius, Galapagos Islands; New Jersey; and Punta 

del Este, Uruguay. There is no information about the extent to which oil or dispersants 

affected sea turtles. 

Selected Case Studies

Although many oil spills have occurred in areas populated by sea turtles, cases 

of large numbers of turtles directly impacted by a spill are very rare. This may be due, 

in part, to the fact that sea turtles have wide ranges and usually are highly dispersed. In 

assessing impacts from past spills, it is important to recognize that the effects of oil on 

sea turtles probably are not well-refl ected by the few reported observations of oiled 

turtles. Documenting the number of turtles affected by an oil spill is diffi cult. Many 

impacted turtles are unlikely to be observed or recovered. Furthermore, most reports 

of spill-related sea turtle impacts are anecdotal, and the cause of death is usually poorly 

documented. Oil spills where impacts to sea turtles have been documented are summarized briefl y below.2

1968 Oil Tanker SS Witwater

The oil tanker SS Witwater ruptured in heavy seas off the Carribean coast of 

Panama on 13 December 1968, spilling over 588,000 gal of diesel and Bunker C oils 

approximately 3.7 km northeast of Galeta Island (NOAA 1992). The oil eventually washed 

onto sand beaches, rocky coasts, and mangroves on Galeta Island. High winds caused a 

spray of mixed seawater and oil to cover trees and shrubs in the suptralittoral zone up to 

2 m above mean high-tide level. Red and black mangrove trees were severely oiled, killing most red mangrove seedlings, the algal community, and invertebrates. Researchers 

also observed dead and dying young sea turtles on oiled mangrove beaches two months 

after the spill, however the exact cause of death was not determined (Rutzler and Sterrer 

1970).
74

1979 Ixtoc I Well Blowout

On 3 June 1979, the Ixtoc I, an offshore exploratory oil well located 80 km off 

Ciudad del Carmen, Mexico, suffered a massive blowout of its wellhead and began 

releasing oil into the Bay of Campeche. Thousands of barrels of oil were released daily 

until the spill was brought under control in late March 1980 (Hooper 1981). The oil drifted 

north, eventually impacting portions of the Mexican and Texas coasts. During the interval 

between the release of oil and its impact on shorelines, weathering signifi cantly altered 

the oil’s original physical and chemical properties, and a water-in-oil emulsion, or mousse, 

formed.

The spill threatened a primary nesting beach of the Atlantic Kemp’s ridley sea 

turtle near Rancho Nuevo, Tamaulipas, Mexico. The nests were aggregated in arribadas 

of thousands of females. In Mexico, hatching begins in mid-June, and the hatchlings 

continue to emerge until mid-September, then swim west and north during the next two 

months.

The Ixtoc I blowout occurred after nesting but before all hatchlings had migrated 

across the beach to the water. Due to concerns that the young turtles would become 

oiled onshore or ingest oil in the water, the Mexican Department of Fisheries (MDF) and 

the U.S. Fish and Wildlife Service (USFWS) planned to airlift approximately 9,000 turtle 

hatchlings if the oil threatened the nesting beach. By July 23, oil was observed less than 

50 km from Rancho Nuevo, so MDF and USFWS moved 9,000 hatchlings to protected 

lagoons, but by July 27 high seas fl owed over islands protecting the lagoons and oil and 

tarballs began washing onto the nesting beach. The 9,000 hatchlings were held on shore 

until July 29 then evacuated by helicopter to a patch of sargassum in clean water less 

than 25 km offshore (Golob and McShea 1980).

More than 200 gal of oil were reportedly recovered during cleanup of the beach 

and lagoons near Rancho Nuevo (Golob and McShea 1980), but oil was still evident 

on the beach during the nesting season the following year (Fritts and McGehee 1982). 

Eventually, oil impacted over 257 km of the south Texas coast, beginning in August and 

September 1979. By the time the oil reached Texas it was highly weathered and had 

washed ashore primarily as tarballs, tarmats, or mousse. Environmentally sensitive, economically important beaches in Texas were cleaned daily using rakes and shovels rather 

than heavy equipment, which removes too much sand. An estimated 7,646 cubic meters 

of oiled sand was removed along the Texas coast (NOAA 1992).

Both live and dead oiled sea turtles were observed along the Texas coast after the 

spill (Lutcavage et al. 1997). Six live green turtles and one live Kemp’s ridley turtle were 

collected during the response. Only one, a green turtle, required cleaning and rehabilitation, and was eventually released (Hall et al. 1983; Hooper 1981). Rabalais and Rabalais 

(1980) reported that in August 1979, fi ve dead juvenile green turtles washed ashore on 

Padre and Mustang Islands, Texas, all heavily fouled with oil, which may have contributed 

MDF - Mexican 

Department of 

Fisheries.
75

to their deaths. Two oiled green turtle carcasses and one oiled young Kemp’s ridley sea 

turtle carcass recovered from Laguna Madre, Texas, were shipped to the federal Patuxent 

Wildlife Research Center to determine cause of death. Autopsies found that while external oil was present on all three turtles (oil was found in the mouth and esophagus and 

all three had evidence of petroleum hydrocarbons in lung, esophageal, intestinal, liver, 

and kidney tissues), but the cause of death could not be determined conclusively (Hall et 

al. 1983). The amount of oil present was considered unlikely to have prevented normal 

movement or have been otherwise fatal. Two of the turtles were in poor condition, but 

had no apparent oil-caused lesions. Hall et al. reported that tissue chemical analysis 

indicated that oil exposure had been chronic, and it was this prolonged exposure that 

may have caused the turtles’ poor body condition, which in turn led to death, either from 

oil toxicity or some another undetermined cause.

Despite early concerns about potential long-term impacts of residual oil affecting orientation cues or hatching success, there is no indication this oil spill signifi cantly 

adversely affected Kemp’s ridley sea turtles (Delikat 1980 and 1981). This conclusion 

is supported by the results of the study by Fritts and McGehee (1982), discussed in 

Chapter 4.

1983 Nowruz Oil Spill

Between January and October 1983, an estimated 42 million gal of oil were 

spilled into the Persian Gulf, primarily from several spills associated with the Iran-Iraq War 

(Miller 1989). In January 1983, oil began to discharge from a well in the Nowruz oil fi eld, 

in Iranian territorial waters. Two other platforms damaged by military action in March 

1983 contributed to the spill, as did other smaller spills and ballast pumping. Large areas 

of sheen, tarballs, and weathered oil rafts were reported in the Persian Gulf during April, 

May, and early June. Oil coated rocky shorelines, sandy beaches of offshore islands, and 

the Saudi Arabian mainland. On sandy beaches, sand movement during several tidal 

cycles buried and fragmented the stranded oil. Tarballs were deposited in the intertidal 

and adjacent subtidal areas of Saudi Arabia, Bahrain, and Qatar.

Between March and mid-April 1983, many dead animals were found along the 

Persian Gulf coast, including over 56 green and hawksbill sea turtles. Only a portion of 

the coastline was monitored, so the number of turtles killed may have been higher. Some 

accounts indicated as many as 180 hawksbill turtles were killed off the islands of Jana 

and Karan (Lutcavage et al. 1997). Burchard (as cited in Miller 1989) estimated that over 

500 sea turtles of both species were killed, representing nearly total annihilation of the 

hawksbill population and a major portion of the green turtle population. The direct and 

indirect impacts to sea turtles from oil on nesting beaches and other sea turtle habitat 

remains unknown but Miller (1989) concluded the impact likely was severe.
76

1984 Oil Tanker Alvenus

The oil tanker Alvenus grounded in the Calcasieu River bar channel, 18 km southeast of Cameron, Louisiana, on 30 July 1984. The hull was ruptured, spilling approximately 

2.7 million gal of medium and heavy Venezuelan crude oils. Rough weather hampered 

offshore recovery efforts, the oil moved slowly westward, eventually washing ashore near 

High Island, along the Bolivar Peninsula, and in Galveston Bay, Texas. Shoreline cleanup 

techniques included using road graders to move beached oil above the high-tide zone. 

During the response, one oiled sea turtle was cleaned and released (NOAA 1992).

1991 Gulf War

Approximately 252 million to 335 million gal of oil were spilled during the Gulf 

War beginning in late January 1991, the largest oil spill ever recorded in the marine 

environment. The major sources were four sunken and leaking vessels, including Iraqi oil 

tankers, and release of oil from the Kuwaiti Mina Al-Ahmadi Sea Island terminal and the 

Iraqi Mina Al-Bakr loading terminal (Al-Majed et al. 2000). An estimated 335 million gal 

spilled directly into the Persian Gulf, forming a 1,554-square-km oil slick. Tarmats up to 30 

cm thick formed on impacted beaches between Safaniya and Abu Ali Island, Saudi Arabia. 

Cleanup operations recovered over 42 million gal by April 1991 (NOAA 1992).

Estimates of the number of sea turtles killed by the oil spilled during the Gulf War 

range from tens to hundreds, but are not well-documented (Lutcavage et al. 1997). One 

stranded green turtle that was recovered and necropsied contained over 4,000 ppm of 

oil in its liver and 310 ppm in its stomach, but no external indication of oil (Lutcavage et 

al. 1997). Interestingly, prior to this spill, recommendations for sea turtle conservation 

in Saudi Arabia had concluded that “...the ongoing high level of oil pollution into the 

Persian Gulf must be substantially reduced if sea turtle populations throughout the 

region are to survive at their current levels” (Miller et al. 1989).

1991 Barge Vista Bella

On 6 March 1991, the Trinidad-registered barge Vista Bella sank in 600 m of water 

about 19.3 km northeast of Nevis Island in the eastern Caribbean, after a towing cable 

snapped. The barge carried around 560,000 gal of No. 6 fuel oil. By March 13, oil, tarballs, 

and oiled debris had washed ashore on sea turtle nesting beaches on the north shore of 

St. Kitts, including Conaree. By March 21, tarballs and tar patties began appearing on St. 

John, and tarballs washed ashore on St. Thomas, St. Croix, Culebra, Vieques, and the main 

island of Puerto Rico shortly thereafter. Several beaches in the British Virgin Islands were 

oiled, and one oiled hawksbill attributed to the spill was recovered near Guayama, Puerto 
77

Rico (Eckert et al. 1992; Eckert and Honebrink 1992). During this incident, the French 

Navy applied the dispersant Finasol OSR7, but details of the application are sketchy.

1993 Barge Bouchard B155

On 10 August 1993, a freighter and two tugs collided in Egmont Channel in lower 

Tampa Bay, Florida. During the collision, the barge Bouchard B155 released 336,000 gal 

of heavy No. 6 fuel oil from one of its cargo holds. By August 15, most of the fl oating oil 

had washed ashore and coated approximately 23 km of sandy beach, several mangrove 

islands, and seawalls. On some sandy beaches, stranded oil was buried by several centimeters of clean sand deposited during high tides. Large, thick oil mats coated mangrove 

roots, oyster beds, seagrass beds, and tidal sand fl ats around four mangrove islands in 

Boca Ciega Bay. The oil was very heavy and emulsifi ed, and large oil patches submerged 

and stabilized in the bay sediments and some offshore areas. Several large, contiguous, thick mats of submerged oil were found just offshore of gulf beaches in 1.8 

to 6 m of water and inside the entrance to Boca Ciega Bay at John’s Pass and Blind 

Pass.

Cleanup of impacted sandy beaches consisted primarily of manually 

removing the surface oil, mechanically removing subsurface oil, and “surf-washing” 

stained sand. Heavy equipment, such as front-end loaders and graders, was used 

for sand removal and surf-washing. Final beach grooming was done with graders 

and disking equipment, normally to a depth of 30 cm. Oil around the mangrove islands 

was vacuumed using grounded barges staged in shallow sand fl ats, followed by manual 

removal within the mangrove edges. Submerged oil patties and tarballs were removed 

manually. Attempts were made to vacuum submerged oil mats west of Eleanor Island in 

Boca Ciega Bay.

Sea turtle nesting beaches and foraging areas were oiled, then disturbed by 

cleanup operations (Figure 6.4). Loggerhead, Kemp’s ridley, green, and hawksbill turtles 

occur in the affected area. The Florida Department of Environmental Protection et al. 

(1997) summarized sea turtle impacts. Loggerhead sea turtles, the most common, were 

impacted most severely: 4 hatchlings were recovered dead, and 12 live hatchlings were 

recovered oiled and were cleaned, rehabilitated, and released. Of these 12, 3 were oiled, 

2 were trapped behind booms with oil, and 7 had no trace of oil but were disoriented 

by lights associated with the response (A. Meylan 20023

). One oiled, live juvenile green 

turtle was recovered offshore in an oiled windrow and was cleaned and released (Figure 

6.5). Many loggerhead nests on beaches in the spill area had not yet hatched: 115 

nests were marked as being at risk, 96 were on oiled beaches, 14 had to be protected 

by booms or trenches, 2 were inundated with oil and subsequently had a lower than 

normal hatching success rate (5 percent of eggs, compared to 50 to 90 percent normally), and 29 hatched during the spill and response. One unmarked nest was run over 

Surf-washing - 

a technique for removing oil from deposited 

beach material in which 

oil or oiled sediments 

are moved to a tidal 

elevation where they 

may be exposed to 

higher levels of wave 

energy (i.e., “washed”). 

The reworking of 

surface or subsurface 

sediments accelerates 

natural degradation 

processes.

Figure 6.4 A nesting beach oiled 

after the 1993 Bouchard B155 spill 

in Tampa Bay, Florida. Photo 

courtesy of Dr. Anne Meylan, 

Florida Marine Research Institute.

Figure 6.5 A juvenile green turtle 

oiled during the 1993 Bouchard 

B155 spill in Tampa Bay, Florida. 

Photo courtesy of Dr. Anne 

Meylan, Florida Marine Research 

Institute.
78

by a bulldozer, crushing 5 eggs; the remaining eggs were transplanted but less than a 

third hatched. Approximately 1,530 loggerhead hatchlings from 23 of the 29 nests that 

hatched were restrained and released into the water in Sarasota County. Approximately 

413 hatchlings from the other 6 nests were not restrained and entered waters that may 

have contained oil. An estimated 27 loggerhead hatchlings from a nest at Egmont Key 

State Park were likely taken by predatory birds after they emerged during the response 

and were impeded from reaching the water by a containment boom left on the beach. 

Overall, approximately 212 hatchlings were killed, and 2,177 were potentially injured by 

oil exposure and response activities.

For more than a year after cleanup, unrecovered submerged and buried oil 

chronically oiled beaches in the Tampa area during storms. In January 2000, several years 

after the spill, submerged oil entrained in bottom sediments of sheltered coastal inlets 

was uncovered during inlet dredging and beach renourishment (Upham Beach) at Blind 

Pass Inlet. Initial dredging operations remobilized the oil, which had weathered very 

little because it was buried. The oil washed ashore as tarballs and patties and coated 

some shorelines. The possibility of mobilization of submerged oil during these activities 

or during storms, as well as placement of dredged oiled sand on renourished beaches, 

caused concern about potential impacts on sea turtle nesting areas. Sea turtles begin 

nesting in the area in early May. A plan was developed to remove the submerged oil in 

Blind Pass and John’s Pass in conjunction with the dredging and beach renourishment 

program. Oil was to be removed from the sand prior to placement on beaches as part 

of the beach renourishment operations. Turtle nesting beaches were monitored and 

surveyed to ensure that no oil was deposited as a result of these operations.

1994 Barge Morris J. Berman

On 7 January 1994, the tank barge Morris J. Berman grounded on hard rocky and 

coral bottom in the surf zone 274 m off San Juan, Puerto Rico. The barge drifted ashore 

after the towing cable parted from its tug. The barge was carrying heavy No. 6 fuel oil, 

which began discharging immediately and impacting nearby shoreline and shallow 

intertidal habitats. Oil was lightered off the Morris J. Berman to another barge, until it 

became too viscous and diffi cult to pump. Oil continued to leak from the barge and re-oil 

the nearshore environment for several days, until the vessel was refl oated, towed to a 

scuttling site 37 km northeast of San Juan, and sunk.

More than 48 km of Puerto Rico’s north shore were ultimately fouled by the 

spilled oil. Two shallow lagoons near the grounding site acted as natural catchment 

areas and oil accumulated on the surface and bottom in large mats. In early February, 

oil impacted shorelines in northwestern Puerto Rico, when a convergence zone concentrated debris and oil was released when the barge was scuttled. Some oil was buried, 
79

forming oily sand layers, and some oil was submerged in sheltered areas and bays in the 

form of oil and sand mats.

Potential impacts to sea turtles and other wildlife were a major concern during 

response. Intensive cleanup efforts began in the affected shoreline areas immediately 

because nesting sea turtles were due to arrive within weeks. Guidelines developed by 

natural resources trustees and response agencies to minimize cleanup impacts 

addressed sand removal, nighttime activities, use of all-terrain vehicles and 

other equipment, and any other cleanup operations that might impact sea 

turtles or their nesting habitats. Sand beaches contaminated with continuous 

oil deposits were cleaned by manual removal, taking precautions to remove 

a minimal amount of clean sand. Heavy equipment, including backhoes and 

front-end loaders, was used to remove large areas of heavily oiled sand and 

buried tarmats. Machinery movements were closely monitored to prevent 

unnecessary traffi c across the beach and sand dunes. Wood-frame and 

chicken-wire screens were used to sieve scattered tarballs out of the sand in some areas. 

Submerged oil was removed manually by divers using manual techniques, vacuum 

transfer units, pumps, and submersible dredges. Beach rock, riprap, and seawalls were 

cleaned with pressure washers and chemical cleaners. Oil in some locations was left to 

weather naturally due to inaccessibility, low levels of human use, or exposure to highenergy waves.

During the response, two oiled green turtles were recovered, cleaned, rehabilitated, and released by the Puerto Rico Department of Natural Resources and Caribbean 

Stranding Network facilities in San Juan. One turtle was oiled on its neck, fl ippers, and 

back; the other one had patchy oiling (Petrae 1995). At least three additional sea turtles 

(one green and two hawksbills), affected by oil that was not attributed to the Berman

spill, were also collected. In addition to turtles, thousands of live and dead oiled organisms washed ashore (Mignucci-Giannoni, 1999), including birds, invertebrates, and fi sh 

(Petrae 1995, Mignucci-Giannoni 1999).

2000 Fort Lauderdale, Florida, Mystery Spill

On 8 August 2000, a spill of unknown origin began washing up along Florida’s 

east coast from North Miami to Pompano. Tarballs from 16 mm to pancake and mat size 

impacted several beaches, sometimes mixed with wrack. The oil was heavy and highly 

weathered. Submerged oil mats and patties, unevenly distributed and of varied sizes 

and thicknesses, were also found in nearshore troughs from John U. Lloyd State Park to 

Hollywood Beach. The submerged oil mats were sticky, mixed with seagrass and sediment, and in some areas continuous, much of it buried under a thin layer of sand. Oiled 

shorelines were manually cleaned within days; some submerged oil was removed manually by divers.

Figure 6.6. Juvenile green turtle 

recovered during the Morris J. 

Berman barge spill in the waters 

off Culebra, Puerto Rico. The 

turtle exhibited signs of eye 

irritation. It was cleaned by 

the Puerto Rico Department of 

Natural Resources and released 

off the island of Vieques. Photo 

courtesy of Bradford

Benggio, NOAA.
80

Hatchling sea turtles were a priority concern during this incident. At the time of 

the spill, an estimated 530 sea turtle nests were on beaches in the area. In John U. Lloyd 

State Park, one of the most heavily impacted areas, 43 surveyed nests were expected to 

hatch within days of the oil stranding. Eight were green turtle nests, the remainder were 

loggerhead nests. In addition to potential impacts from shoreline oiling, the submerged 

oil and tarballs presented a serious risk to hatchlings and turtles swimming nearshore. 

Known sea turtle nests were monitored 24 hours a day, and hatchlings were 

captured for release in clean areas. Beaches were monitored for new tarball strandings 

and cleaned immediately. Stricter cleanup standards were established for turtle nesting 

beaches than other impacted areas (no more than 5 percent oil cover). Volunteers raked 

areas seaward of turtle nests to clear wrack and tarballs.

More than 137,000 loggerhead, green, and leatherback hatchlings (hatched 

within the previous 30 days) were estimated to be in the area and potentially exposed 

to oil. Natural Resource Damage Assessment (NRDA) modeling estimated that over 70 

adult (mostly nesting females), and over 300 post-pelagic juvenile sea turtles in the area 

were potentially exposed to oil. The model also indicated that some sea turtles were 

likely killed by the oil, even though no oiled turtles were recovered. The model estimate 

for hatchling mortality was 7,800. Loggerheads, which are most abundant in the area, 

were presumed most seriously impacted; green and leatherback turtles were presumed 

affected to a much lesser extent.

2001 Auxiliary Oiler USS Mississinewa

In November 1944, the U.S. Navy auxiliary oiler USS Mississinewa was sunk by 

a Japanese manned suicide torpedo in Ulithi Lagoon, Yap Island, Federated States of 

Micronesia. The vessel was reportedly loaded with 440,000 gal of aviation gasoline and a 

full load of fuel oil. The Mississinewa rested on the bottom for decades, but in July 2001 a 

tropical storm disturbed the wreck site and oil leaked to the surface.

The island group comprising Ulithi Atoll is quite large and is one of the most 

important green and hawksbill aggregating and nesting areas in the western Pacifi c 

Ocean. Although comprehensive population surveys had not been conducted, several 

hundred green turtles were counted and tagged during a census undertaken shortly 

before the spill (S. Kolinski 20014

); about 1,000 migratory (nonresident) green turtles 

were estimated to use the atoll each year. The timing of the oil release (reported to U.S. 

authorities in August 2001) was of particular concern: it was about the expected peak 

during hatching.

No impacts to turtles were reported during the shoreline surveys or salvage 

operations that followed. Turtles are an important aspect of Ulithi native society, providing food and representing a central focus for mythology and a cultural governance 

system extant for hundreds of years: “ . . . myth-makers have served to endow the sentiNRDA - 

Natural Resource 

Damage Assessment.
81

ment toward sea turtles with an aura of antiquity and sacredness . . .” (Lessa 1984). To the 

extent that strict cultural traditions strongly infl uence turtle harvests in the islands, they 

represent a de facto conservation ethic. A catastrophic incident affecting the continued 

viability of sea turtles in the region would have far-reaching effects, to the turtles and to 

the social fabric of the human inhabitants. The deterioration of that social fabric would 

further weaken traditional controls on harvest, accelerating the demise of the region’s 

turtles.

Impacts of Tarballs

Impacts on sea turtles of tarballs not associated with a particular oil spill have 

been documented frequently (Carr 1987). Witham (1983) reported several instances of 

small sea turtles impacted by oil or tar along the Florida coast. In many cases, tar sealed 

the mouths and nostrils of the small turtles, and several turtles had ingested tarballs.

Witherington (1994) found that over 34 percent of post-hatchling sea turtles 

captured and examined in the Atlantic Ocean off Florida in 1993 contained tar in their 

stomachs and esophagi, and over half of the turtles had tar caked in their jaws. A subsequent survey of 66 neonate loggerhead turtles captured in downwelling lines near the 

Gulf Stream front off Florida (Witherington 2002) documented ingested tar in 20 percent 

of them. Chemical analysis of the tar samples indicated multiple sources and degrees of 

weathering.

Van Vleet and Pauly (1987) chemically analyzed tar found in or on several 

stranded sea turtles collected along the Florida coast and throughout the Gulf of 

Mexico; they concluded the tar had originated from crude oil tanker discharges. They 

also reported that analysis of internal organs and feces from dead and live sea turtles 

indicated that turtles actively ingest fl oating oil and that oil residues may remain in the 

turtles’ digestive tracts for several days. The researchers suggested that crude oil tanker 

discharges are having a signifi cant impact on marine turtle populations in the eastern 

Gulf of Mexico.

Oil-Related Strandings

It has been estimated that approximately 1 percent of annual sea turtle strandings are associated with oil.5

 Higher percentages are attributed to oil in South Florida (3 

percent) and Texas (3 to 6 percent) (Lutcavage et al. 1997), while much lower percentages 

characterize strandings in Hawaii (one individual in 18 years) (G. Balazs 200221). Specifi c 

counties in Florida and Texas reported high rates for particular years (over 37 percent, 

for example, in Dade County, Florida). Work by Vargo et al. (1986) indicated that juveniles 

are more affected than adults and that certain species, such as green turtles, are more 

affected than others, perhaps due to habitat preference and location of nesting beaches. 

Neonate - 

post-hatchling.
82

Among the impacted sea turtles, tar is often found in the mouth, esophagus, or stomach, 

particularly in hatchlings and young turtles. Small sea turtles have been found completely mired in oil. Oil removed from stranded sea turtles in Florida and Texas has been 

identifi ed primarily as tanker discharges.

Bugoni et al. (2001) recovered and examined dead, stranded sea turtles on the 

coast of Brazil and found that oil was a relatively minor occurrence in the green turtles 

examined between 1997 and 1998. Of 38 individuals examined, only one contained oil. 

By far, plastic debris (bags and ropes) was the most common anthropogenic material 

found (in 16 and 15 individuals, respectively).

The Future

While we cannot predict the future, trends over the past 20 to 30 years provide 

clues to what could happen in the coming decade. The typical tropical spill that NOAA 

responded to during the past decade involved a vessel grounded nearshore and spilling 

about 4000 gal of diesel or No. 2 fuel oil. The typical vessel was a freighter, bulk carrier, 

or fi shing vessel. This would suggest that, in the United States, to protect sea turtles and 

their habitats response planners should anticipate small- and medium-sized nearshore 

fuel oil spills. However, this will not be the case for other parts of the world’s oceans, 

where the prevalent oil types and transportation modes differ.

Concerns

Review of the case history fi les permits us to defi ne some areas of concern or 

improvement. For example, listing sea turtles in a spill notifi cation phase has not always 

been consistent: turtles are sometimes listed as resources at risk, and other times not. 

During 1992 to 2001, sea turtles or turtle habitat were a concern in only about half the 

actual or potential spills within their nominal range. Turtles and nesting beaches are 

more frequently mentioned in response progress reports, but in many cases were not 

mentioned at all, even for incidents that occurred in turtle territory. This suggests that the 

incidents were either not considered a real risk despite the potential or (less likely) the 

threat was simply overlooked.

The body of case histories does not refl ect a pattern of signifi cant impact of oil 

spills on sea turtles. Thus, it is possible that sea turtles have not been seriously affected 

by spills. It is also possible that impacts on turtles were not reported because impacted 

individuals were not observed or were only discovered after response actions were 

terminated. If that is the case, more work is needed to connect damage assessment and 

restoration information to response information.

While the public and media tend to view crude oil spills from large tankers as 

threats to wildlife, most incidents were from vessels other than tankers and from station-
83

ary sources such as pipelines and dock facilities. This distribution among spill sources 

is consistent with other larger assessments, such as that done by the National Research 

Council (2002). Most knowledge about the effects of oil on sea turtles—scant as it is—is 

based on exposures to crude oil, but we now realize that information is also needed 

about effects of fuel oils and dispersed oil, and effectiveness of shoreline and nest site 

protection strategies. While it seems unlikely that intentional oil exposure experiments 

with live sea turtles will be permitted or accepted anytime in the near future, other biochemical or molecular assays that could be performed ex situ may be one way to obtain 

toxicological information without harming or stressing threatened turtles.

For Further Reading

Al-Majed N., H. Mohammadi, and A. Al-Ghadban. 2000. Regional report of the state of the environment. 

ROPME/GC-10/001/1. Revised by A. Al-Awadi, Regional Organisation for the Protection of the Marine 

Environment, Kuwait. 178 p.

Bugoni, L., L. Krause, and M. V. Petry. 2001. Marine debris and human impacts on sea turtles in southern Brazil. 

Mar. Poll. Bull. 42(12): 1330–1334.

Carr, A. 1987. Impact of nondegradable marine debris on the ecology and survival outlook of sea turtles. Mar. 

Poll. Bull. 18: 352-356. 

Delikat, D. S. 1980. IXTOC I oil spill and Atlantic ridley survival. In: Coastal Zone 1980, Volume I, B. L. Edge, ed. 

American Society of Civil Engineers, New York. pp. 312–319.

Delikat, D. S.. 1981. IXTOC I oil spill—Atlantic ridley sea turtle survival. Underwater Nat. 13(1): 13–15.

Eckert, K. L., and T. D. Honebrink. 1992. WIDECAST sea turtle recovery action plan for St. Kitts and Nevis, CEP 

Technical Report No. 17, UNEP Caribbean Environment Programme, Kingston, Jamaica. 116 p.

Eckert, K. L., J. A. Overing, and B. B. Lettsome. 1992. WIDECAST sea turtle recovery action plan for the British 

Virgin Islands, CEP Technical Report No. 15, UNEP Caribbean Environment Programme, Kingston, Jamaica. 

116 p.

Florida Department of Environmental Protection, National Oceanic and Atmospheric Administration, and U.S. 

Department of the Interior. 1997. Damage assessment and restoration plan/environmental assessment for 

the August 10, 1993, Tampa Bay oil spill: Volume I —ecological injuries. NOAA Restoration Center, Southeast 

Region, St. Petersburg, Fla. pp. 47–51.

Fritts, T., and M. A. McGehee. 1982. Effects of petroleum on the development and survival of marine turtle 

embryos. FWS/OBS-82/37 Contract NO. 14-16-0009-80-946. U.S. Fish and Wildlife Service, U.S. Dept. of the 

Interior, Washington, D.C.

Golob, R., and D. McShea. 1980. Special report: Ixtoc I. Oil Spill Intelligence Rept. 3(1): 1–36.

Hall, R. J., A. A. Belisle, and L. Sileo. 1983. Residues of petroleum hydrocarbons in tissues of sea turtles exposed 

to the Ixtoc I oil spill. J. Wildl. Diseases 19(2): 106–109.

Hooper, C. H., ed. 1981. The IXTOC I oil spill: The federal scientifi c response. NOAA Hazardous Materials 

Response Project, Boulder, Colo. 202 p.

Hutchinson, J., and M. Simmonds. 1992. Escalation of threats to marine turtles. Oryx 26: 94–103.

Lessa, W. A. 1984. Sea turtles and ritual: Conservations in the Caroline Islands. In: The Fishing Culture of the 

World: Studies in Ethnology, Cultural Ecology and Folklore, Volume II, B. Gunda, ed. Akadémiai Kiadó, Budapest. 

pp. 1183–1201.
84

Lutcavage, M. E., P. Plotkin, B. Witherington, and P. L. Lutz. 1997. Human impacts on sea turtle survival. In: The 

Biology of Sea Turtles, P. L. Lutz and J. A. Musick, eds., CRC Press Inc., Boca Raton, Fla. pp. 387–409.

Lutz, P. L., and M. Lutcavage. 1989. The effects of petroleum on sea turtles: Applicability to Kemps’ ridley. 

In: Proceedings of the First International Symposium on Kemp’s Ridley Sea Turtle Biology, Conservation and 

Management, C. W. Caillouet, Jr. and A. M. Landry, Jr., eds. TAMU-SG89-105, Texas A&M University Sea Grant 

Program, Galveston. pp. 52–54.

Mignucci-Giannoni, A. A. 1999. Assessment and rehabilitation of wildlife affected by an oil spill in Puerto Rico. 

Environ. Poll. 104: 323–333.

Miller, J. D. 1989. Recommendations for the conservation of marine turtles in Saudi Arabia, Volume I. MEPA 

Coastal and Marine Management Series Report No. 9. Meteorological and Environmental Protection 

Administration (MEPA), Ministry of Defence and Aviation, Kingdom of Saudi Arabia. 63 p.

Miller, J. D., C. J. Limpus, and J. P. Ross. 1989. Recommendations for the conservation of marine turtles in Saudi 

Arabia, Volume II. MEPA Coastal and Marine Management Series Report No. 9. 209 p.

National Research Council 2003. Oil in the Sea III: Inputs, Fates, and Effects. National Academy Press, Washington, 

D.C. 265 p.

National Oceanic and Atmospheric Administration (NOAA). 1992. Oil spill case histories: 1967–1991. 

Summaries of signifi cant U.S. and International Spills. Report No. HMRAD 92-11 to the U.S. Coast Guard 

Research and Development Center. Hazardous Materials Response and Assessment Division, National Oceanic 

and Atmospheric Administration, Seattle, Wash.

Petrae, Gary, ed. 1995. Barge Morris J. Berman spill: NOAA’s scientifi c response. HAZMAT Report No. 95-10. 

Hazardous Materials Response and Assessment Division, National Oceanic and Atmospheric Administration, 

Seattle, Wash. 63 p.

Rabalais, S. C., and N. N. Rabalais. 1980. The occurrence of sea turtles on the south Texas coast. Contrib. in Mar. 

Sci. 23: 123–129.

Rutzler, K., and W. Sterrer. 1970. Oil pollution damage observed in tropical communities along the Atlantic 

seaboard of Panama. Bioscience 20: 222–224.

Van Vleet, E. S., and G. G. Pauly. 1987. Characterization of oil residues scraped from stranded sea turtles from 

the Gulf of Mexico. Caribbean J. Sci. 23: 77–83.

Vargo, S., P. Lutz, D. Odell, E. Van Vleet, and G. Bossart. 1986. Effects of oil on marine turtles, Volume 1: Executive 

summary. Florida Institute of Oceanography. Final Report MMS NO 14-12-0001-30063. 12 p.

Vargo, S., P. Lutz, D. Odell, E. Van Vleet, and G. Bossart. 1986. Effects of oil on marine turtles, Volume 2: Technical 

report. Florida Institute of Oceanography. Final Report MMS NO 14-12-0001-30063. 180 p.

Witham, R. 1978. Does a problem exist relative to small sea turtles and oil spills? In: Proceedings of the 

Conference on the Assessment of Ecological Impacts of Oil Spills, Keystone, Colo. American Institute of Biol. 

Science. pp. 630–632.

Witham, R. 1983. A review of some petroleum impacts on sea turtles. In: Proceedings of a Workshop on 

Cetaceans and Sea Turtles in the Gulf of Mexico: Study Planning for Effects of Outer Continental Shelf Development, 

C. E. Keller and J. K. Adams, eds. USFWS/OBS-83/03. Prepared by the U.S. Fish and Wildlife Service for the 

Minerals Management Service, Metairie, La. 42 p.

Witherington, B. E. 1994. Flotsam, jetsam, post-hatchling loggerheads, and the advecting surface smorgasbord. In: Proceedings of the 14th Annual Symposium of Sea Turtle Biology and Conservation, Miami, Florida, K. A. 

Bjorndal, A. B. Bolten, D. A. Johnson, and P. J. Eliazar, eds. NOAA Technical Memorandum NMFS-SEFSC-351. pp. 

166–168.

Witherington, B. E. 2002. Ecology of neonate loggerhead turtles inhabiting lines of downwelling near a Gulf 

Stream front. Mar. Biol. 140: 843–853.
85

Chapter Notes

1

 By comparison, the Exxon Valdez spill in Prince William Sound, Alaska, was 10.9 million gal.

2 This listing is not comprehensive.

3

 A. Meylan, Florida Fish and Wildlife Conservation Commission, Florida Marine Research Institute, 100 Eighth 

Avenue SE, St. Petersburg, FL 33701-5095, personal communication, 2002. 

4

 S. Kolinski, Department of Zoology, University of Hawaii at Manoa, 2538 McCarthy Mall, Honolulu, HI 96822, 

personal communication, 2001

5

 As identifi ed by the U.S. Sea Turtle Stranding and Salvage Network.

6

 G. Balazs, Marine Turtle Research Program, NOAA/NMFS Southwest Fisheries Science Center, 2570 Dole 

Street, Honolulu, HI 96822-2396, personal communication, 2002.

Conclusions

We have presented a large amount of material for your consideration in this 

document. Our intent was to consolidate a body of disparate information on sea turtles 

into a single place, and interpret it within the framework of oil effects and spill response 

activities. Our conclusions include the following:

· Six species of sea turtles are found in the United States or in U.S.-territorial waters: 

leatherback, green, Kemp’s ridley, hawksbill, loggerhead, and olive ridley.

· All six turtle species are listed under the Endangered Species Act, thus are subject to 

special protection.

· Sea turtles worldwide are threatened by a variety of natural and anthropogenic 

infl uences. Among those of human origin, incidental catch and death in fi sheries for 

other species is the most prevalent.

· Aspects of the life histories of sea turtles place them at heightened risk due to the 

intersection and overlap with areas where oil collects.

· Even though direct exposure studies are quite limited, there is strong, if dated, 

information that indicates oil is harmful to turtles. Dermal tissues and membranes 

appear to be particularly sensitive to exposure.

· Fresh oil harms sea turtle eggs; weathering reduces the toxic effect.

· Spills in which turtle injury has been documented are relatively rare.

· The threat from oil spills was demonstrated by Ixtoc I, in which the only known 

nesting site for a highly endangered turtle species was narrowly missed, and by the 

growing transport of petroleum products across waters representing important 

turtle habitat.

· In the U.S. waters where sea turtles are found, historical records suggest that the 

most prevalent spills have involved refi ned fuel oils from barges or freighters and 

have occurred as a result of vessel grounding.

· Response activities have the potential to adversely affect sea turtles, both on the 

water and on the beach. Probably the greatest potential for impact exists in beach-
86

related oiling and cleanup, which could disturb nesting females, nests, and hatching 

turtles, due to the large numbers of animals that could be affected in a relatively 

small area.

Our goal in structuring a response to an oil spill in sea turtle habitat will be 

to evaluate the tradeoffs of various actions against the effects to all of the identifi ed 

resources at risk. When sea turtles are judged to be a priority for protection, then we can 

modify the response to accommodate some of the many special aspects of sea turtle 

biology that have been discussed here and elsewhere. While we are not likely to completely eliminate spill-related stress to potentially affected animals, we may be successful 

in reducing one source of stress to these threatened populations. In doing so, we improve 

their chances for survival in an increasingly challenging ocean environment.

Photo courtesty of Dr. Asaf Senol, Department of 

Environmental Protection, Ministry of Tourism and 

Environment, Turkish Republic of Northern Cyprus.
87

Glossary

ACP: Area Contingency Plan

albedo: ratio of solar energy refl ected from an object to solar energy received by it.

arribada: mass nesting aggregation; Spanish, meaning literally, “arrived.”

ATSDR: Agency for Toxic Substances and Disease Registry, U.S. Department of Health and Human 

Services.

bbl: petroleum barrel, equal to 42 U.S. gal.

beach renourishment: replenishment of beach sand by mechanically dumping or pumping sand onto 

an eroded beach; also referred to as beach nourishment.

brevetoxicosis: a deadly condition caused by ingestion of dinofl agellate organisms often responsible 

for red tides; recently linked to deaths of manatees in Florida and common murres in California.

Calipee: cartilage

carapace: dorsal (top) shell of a turtle.

cheloniid: hard-shelled sea turtles composed of the genera Chelonia, Caretta, Lepidochelys, 

Eretmochelys, and Natator; contrast to dermochelyid.

CITES: Convention on International Trade in Endangered Species of Wild Fauna and Flora.

dermochelyid: leathery-shelled sea turtles (i.e., leatherback).

diverticulum: an abnormal saclike pouch projecting from a defect in the wall of a tube or cavity.

endangered: Any species of animal or plant that is in danger of extinction throughout all or a signifi -

cant part of its range (from the Endangered Species Act of 1973).

ESI: Environmental Sensitivity Index map.

fi bropapilloma: a tumor-forming, debilitating, and often fatal disease of sea turtles, manifested by 

formation of multiple fi brous masses of tissue 1 mm to 30 cm in diameter growing from the eyes, fl ippers, neck, tail, scutes, and in the mouth.

FP: see fi bropapilloma.

hematocrit: red blood cell volume.

hemorrhagic enteritis: bleeding infl ammation of the intestine.

in-situ burning: response technique in which spilled oil is burned in place.

lachrymal gland: tear glands highly modifi ed to excrete excess salt.

Langmuir cell: individual counter-rotating vortices (i.e., one rotates clockwise, the next counter 

clockwise, the next clockwise, etc.), resulting in the commonly observed “windrows” in which fl otsam 

is arranged in rows paralleling the wind direction. At boundaries between the cells, water is moving 

either up or down. Where it is moving down, the surface water is converging (being pulled together), 

and any surface objects will be pulled into the boundary line between the cells; where the water is 

moving up between the cells, the water diverges, and no material collects.

MDF: Mexican Department of Fisheries.

MMS: U.S. Minerals Management Service (U.S. Department of the Interior).

nares: external nostrils.
88

neonate: post-hatchling.

NMFS: National Marine Fisheries Service (NOAA).

NOAA: National Oceanic and Atmospheric Administration. (U.S. Department of Commerce).

NRDA: Natural Resource Damage Assessment.

oleophilic: oil-attracting.

osmolarity: the concentration of an osmotic solution, especially when measured in osmols or milliosmols per liter of solution.

phalanges: long “fi nger” bones of a turtle fl ipper.

plastron: ventral (bottom) shell of a turtle.

PM10: particles with an aerodynamic diameter less than or equal to a nominal 10 micrometers.

ppm: parts per million.

pyrosoma: pelagic colonial tunicate; most species inhabit tropical waters, with some up to 4 m in 

length.

RAR: resources at risk.

sargassum: genus of brown algae, also known as gulfweed. There are 15 species in the genus, and each 

has air bladders. Some species are free fl oating. Off the U.S. coast, south of Bermuda, is the Sargasso 

Sea, a large (two-thirds the size of the United States), loosely-defi ned portion of the Atlantic Ocean 

where an estimated 7 million tons of live sargassum may be found.

SCL: straight carapace length.

scute: plates of the sea turtle shell.

Section 7 consultation: requirement under the Endangered Species Act for federal agencies to address 

potential impacts of their actions on threatened species.

surf-washing: a technique for removing oil from deposited beach material in which oil or oiled 

sediments are moved to a tidal elevation where they may be exposed to higher levels of wave energy 

(i.e., “washed”). The reworking of surface or subsurface sediments accelerates natural degradation 

processes.

STSSN: Sea Turtle Stranding and Salvage Network.

TED: turtle excluder device, an adaptation to commercial shrimp nets to permit sea turtles to escape.

threatened: any species likely to become endangered in the foreseeable future (from the Endangered 

Species Act of 1973).

USFWS: U.S. Fish and Wildlife Service (U.S. Department of Interior).

weathering: the alteration of the physical and chemical properties of spilled oil through a series of 

natural biological, physical, and chemical processes beginning when a spill occurs and continuing as 

long as the oil remains in the environment. Contributing processes include spreading, evaporation, 

dissolution, dispersion, photochemical oxidation, emulsifi cation, microbial degradation, adsorption to 

suspended particulate material, stranding, or sedimentation.
89

Appendix A: Protocol for Recovery of Oiled Marine 

Turtles at Sea

Produced as guidance during the 1993 Bouchard B155 oil spill in Tampa Bay, Florida, by the Florida Fish and 

Wildlife Conservation Commission, Florida Marine Research Institute

Reproduced with permission of the Florida Fish and Wildlife Commission.

Protocol for Recovery of Oiled Marine Turtles at Sea

1. Bring turtle on board (dipnets are useful for small turtles).

2. Determine health status (live, dead, injured) and degree of fouling by oil.

3. Determine position at sea (latitude/longitude, Loran reading, GPS coordinates, 

landmarks, etc.).

4. Contact the Florida Marine Patrol to report the recovery of the turtle, and inform 

them whether you can transport the turtle to the Pinellas Oiled Wildlife Response 

Center at Fort Desoto. Alert the Response center that a turtle is being brought in and 

estimate your time of arrival. Turtles should be brought in as soon as possible.

5. If the turtle is alive, keep it out of the sun and keep it moist with towels or wet it 

frequently. Do not put it in water in which it can submerge.

6. If a camera is available, take a few photographs of the animal to document its 

condition at the time of recovery.

7. Record the place and time of discovery of the animal and any relevant information 

about oil conditions at the site to pass on to the Wildlife Response Center. Provide 

your full name and contact numbers.

8. Deliver the animal to the Pinellas Oiled Wildlife Response Center at Fort Desoto.

9. Turtles found dead or that die in transit should be kept cool (with ice, refrigerator, 

freezer, shade) until transferred to the Response Center.

Protocol communicated by:

Dr. Anne Meylan

Florida Marine Research Institute

Florida Fish and Wildlife Conservation Commission

100 Eighth Avenue SE

St. Petersburg, FL 33701-5095
90

APPENDIX B: Excerpted Sections from Marine 

Turtle Guidelines, State of Florida Fish and Wildlife 

Conservation Commission

Note: Included as an informational reference only. Spill responders are not authorized to perform these 

activities unless specifi cally permitted by state and federal agencies.

Reproduced with permission of the Florida Fish and Wildlife Conservation Commission

Full citation:

Florida Fish and Wildlife Conservation Commission. 2002. Sea Turtle Conservation Guidelines, April, 2002 

Revision. Florida Fish and Wildlife Conservation Commission, Tallahassee, Florida. 61 pp. + appendices.

SECTION 2 - NESTING BEACH SURVEY ACTIVITIES 

Summary

If your permit authorizes you to conduct nesting surveys you are also authorized 

to conduct the following activities:

· mark nests 

· conduct hatching success evaluations

· rescue and release hatchlings 

Unless specifi cally stated on the permit, personnel are NOT authorized to conduct 

the following activities:

· relocate nests

· screen nests with self-releasing screens/cages

· screen nests with restraining cages

· use a self-releasing hatchery

· use a restraining hatchery

· use probes (other than fi ngers) to locate clutches

· conduct nighttime surveys

· conduct public hatchling releases
91

Activity Description

This activity involves the daily survey of a specifi c beach area (as specifi ed on 

the permit) to identify, enumerate, and evaluate nesting activities. In nesting surveys, 

surveyors count and identify “crawls,” which are the marks left in the sand by sea turtles 

that have attempted to nest. The offi cial sea turtle nesting season varies across the state 

due to geographic differences in the seasonality among the various sea turtle species. 

For most of the state, nesting season is between May 1, when loggerheads begin nesting, 

and October 31, after which period most nests of each species have hatched. In Brevard 

through Broward Counties, where the majority of leatherback nesting occurs, nesting 

season is between March 1 and October 31.

For best viewing of crawls, nesting surveys should begin shortly after sunrise but 

never earlier than 1⁄2 hour before sunrise. Because of potential disturbances to nesting 

females and the diffi culty of locating and interpreting crawls in the dark, nesting surveys 

may not be conducted at night. 

Surveyors should traverse the beach along (and seaward of, if possible) the most recent high tide line. This is important not only for ensuring 

that turtle crawls are not obscured before they can be evaluated, but also for 

avoiding impact to nesting Wilson’s plovers and other nesting shorebirds. 

Surveyors should become familiar with and keep alert for shorebird chicks 

in the intertidal zone as well, since they use this habitat once they leave their 

nests. For additional information on how to identify and protect shorebirds, 

contact FWC’s Division of Wildlife at (850) 488-3831. You can also contact the 

USFWS (USFWS, Migratory Birds and State Programs, 1875 Century Boulevard, 

Suite 240, Atlanta, GA 30345-3301).

Upon discovery of a crawl, surveyors should make a visual determination as 

to whether the crawl was a nesting emergence (i.e., a nest) or non-nesting emergence 

(often called a “false crawl”); they should also determine what species of turtle made the 

crawl. All crawls should be recorded on a data sheet. If a crawl is clearly identifi able as 

a nest and the nest does not have to be screened, caged, precisely marked, or relocated, 

the surveyor should not dig into the nest simply to verify the presence of eggs. After 

each crawl is evaluated and documented, the tracks should be marked to avoid duplicate 

reporting. To accomplish this, a surveyor may obliterate a section of the upper track (not 

the nest site) by sweeping his/her feet across the track (Figure 2-1) or by crossing over 

the track (well above the high tide mark but not over the clutch) with a survey vehicle 

(Figure 2-2).

Nesting surveys may only be conducted within the boundaries specifi ed on the 

permit. Ideally, boundaries should not change, either within a season or from year to year. 

Requests for expansion of authorized nesting survey areas must be submitted in advance 

and in writing to FWC, Bureau of Protected Species Management. It is imperative that 

Figure 2-1. Crawl crossed out 

using foot.

Figure 2-2. Crawl crossed out 

using ATV.
92

survey areas do not overlap. Please inform FWC immediately of any reduction in survey 

efforts so that steps can be taken to ensure continuity in nesting beach coverage. It is 

extremely important that FWC be informed of any changes in monitoring effort in order 

to maintain accurate and consistent nesting survey records.

Survey boundaries should be permanent and specifi c. GPS coordinates are highly 

desirable, in addition to physical landmarks such as state roads, county lines, etc. Street 

addresses are preferable to condominium names, which may change at any time. FWC 

has latitude and longitude coordinates, most collected with differentially corrected GPS, 

for every INBS beach and for all zones within these beaches. If INBS zone markers are lost, 

contact FWC for the coordinates that would allow correct repositioning of missing zone 

markers.

SPECIES IDENTIFICATION AND DETERMINATION OF NESTING SUCCESS

The tracks and other evidence left on the beach after a sea turtle has emerged 

(crawls) can be used to identify what species of turtle came up and whether or not it 

nested. The following outline describes how to use crawl evidence to make these identifi cations.

I. Identify which is the incoming (emerging) track and which is the outgoing (returning) track.

· As a turtle crawls it pushes sand backward with each fl ipper stroke.

· If one track is shorter, it will be the incoming track (Figure 2-3).

· If tracks overlap, the outgoing track will be on top.

II. What species made the crawl (loggerhead, green turtle or leatherback)? Note: 

Although hawksbills and Kemp’s ridleys occasionally nest on Florida beaches, nesting is rare and their crawl and nest-site characteristics are similar to the loggerhead. 

Minimal discussion will be provided below for hawksbills and Kemp’s ridleys. (Track 

widths listed below for loggerhead, green turtle, and leatherback were provided by 

Erik Martin, EAI. All artwork was provided by Dawn Witherington).

Figure 2-4: tracks from a sea turtle with an alternating gait, no tail drag mark, and 

track width typically ranging from 70 to 124 cm (27.6 to 48.8 inches) with a mean of 94 

cm (37.0 inches): loggerhead turtle (Caretta caretta). Species with similar tracks: hawksbills (Eretmochelys imbricata) typically leave a wavy tail-drag mark near the track center 

(Figure 2-5) and hawksbill track widths typically range from 70 to 85 cm (27.5 to 33.5 

inches). Kemp’s ridley (Lepidochelys kempii) seldom leave a conspicuous tail-drag mark 

and a ridley track width ranges from 70 to 80 cm (27.6 to 31.5 inches). Both hawksbills 

and Kemp’s ridleys crawl with an alternating gait, like loggerheads. Kemp’s ridleys are 

Figure 2-3. Incoming vs. 

outgoing track (this turtle had a 

right rear fl ipper injury). 
93

Figure 2-4. Loggerhead track

Figure 2-5. Hawksbill and 

Kemp’s ridley tracks.

Kemp’s ridley tracks. Hawksbill tracks.

Figure 2-6. Green turtle track

Figure 2-7. Leatherback track

predominantly daytime nesters. If you fi nd a turtle nesting during the daytime, be sure 

to look at it closely (and take pictures if possible) to determine its species. Kemp’s ridleys 

also pack the sand down by rocking their bodies from side to side during nest covering 

(unlike the other species that use their rear fl ippers to “knead” sand to compact it).

Figure 2-6: tracks from a sea turtle with simultaneous limb movement, a center 

drag mark from the tail (the center drag mark may be a solid or broken line), and track 

width typically ranging from 95 to 144 cm (37.4 to 56.7 inches) with a mean of 119 cm 

(46.8 inches): green turtle (Chelonia mydas).

Figure 2-7: tracks from a sea turtle with simultaneous limb movement, a center 

drag mark from the tail, and track width typically ranging from 175 to 214 cm (68.9 to 
94

84.3 inches) with a mean of 196 cm (77.2 inches); track path sometimes circling or sinusoidal (S-shaped): leatherback turtle (Dermochelys coriacea).

Note: Flipper injuries to turtles may alter track appearance (Figure 2-8). 

Characteristics of the nest (given below) should be used in conjunction with track characteristics to identify species.

If the crawl is from a loggerhead, is it a nest or a non-nesting emergence? It is 

important to record both types of emergences. One should NOT dig into the nest to 

confi rm the presence of eggs unless the nest is to be screened, caged, or marked for later 

determination of hatching success.

A. Identify emerging and returning tracks by their direction (see I.).

B. Follow the path taken by the turtle and look for the following attributes.

1. Evidence of covering the nest with the front fl ippers (Figure 2-9). If present, the crawl can be considered a NEST.

a. Presence of a secondary body pit and/or escarpment.

b. Sand “misted” or “thrown” over the emerging track.

2. Evidence of an abandoned nesting attempt. If present, the crawl can be 

considered a NON-NESTING EMERGENCE (i.e., false crawl).

a. Very little or no sand disturbed other than tracks (Figure 2-10).

b. Back stop with sand pushed back (not thrown) over emerging crawl, typically between two mounds of sand piled by the front fl ippers during construction of the primary body pit (Figure 2-11).

c. Considerable amount of sand disturbed from a digging effort, but with the 

crawl exiting the disturbed area and continuing toward the dune before 

turning toward the ocean (Figure 2-12).

d. Considerable amount of sand disturbed from a digging effort, but with a 

smooth-walled or abandoned/open egg chamber (15–25 cm diameter) in 

the center of a pit within the disturbed area (Figure 2-13).

IV. If the crawl is from a green turtle, is it a nest or a non-nesting emergence?

A. Identify emerging and returning tracks by their direction (see I. above).

B. Follow the path taken by the turtle and look for the following attributes.

1. Evidence of front fl ipper covering. If present, the crawl can be considered 

a NEST.
95

Figure 2-8. Loggerhead turtle track with 

right rear fl ipper injury.

Right front fl ipper mark

Left rear fl ipper mark

Right rear fl ipper mark

Figure 2-9. A loggerhead nest site showing a secondary body pit (A) 

and a mound of thrown sand that is wider than the track.

Figure 2-10. A loggerhead false crawl showing no evidence of disturbed 

sand other than the track.

Figure 2-11. A loggerhead false crawl showing a small abandoned 

primary body pit (C) and a mound of pushed sand (D) no wider 

than the track and lying between two conspicuous ridges.

Figure 2-12. A loggerhead false crawl showing an abandoned primary body 

pit (C) and a mound of pushed sand (D) no wider than the track and lying 

between two conspicuous ridges. As is rarely found in nests, a track continues up 

the beach from the site where the turtle’s last digging occurred.
96

a. Sand thrown into a mound covering more than 2 m of the emerging 

track and a deep (20–50 cm) secondary body pit with an escarpment 

(Figure 2-14).

2. Evidence of an abandoned nesting attempt. If present, the crawl can be 

considered a NON-NESTING EMERGENCE.

a. Very little or no sand disturbed other than tracks (Figure 2-15).

 Less sand thrown over the emerging track and a smaller body pit than 

described in 1a above.

V. If the crawl is from a leatherback turtle, is it a nest or a non-nesting emergence?

A. If the disturbed sand in the crawl covers a large expanse of beach (>4 square 

meters) with sand thrown in multiple directions, the crawl can be considered 

a NEST.

B. If the crawl is less extensive than in A, the crawl can be considered a NONNESTING EMERGENCE.

Note: The extent of the excavations described for all species above will be infl uenced by vegetation, sand compaction, and objects encountered by turtles while digging. 

There is some variation in the behavior of turtles, and the above guidelines will not lead 

to a correct determination in every case. They are offered solely to help you with the task 

of determining whether a nest has been made.

NEST MARKING

Not every sea turtle nest needs to be marked. Marking is necessary for protection 

from hazardous activities being conducted on the beach or to obtain information on 

reproductive (hatching) success. Nest-marking methods for each of these two objectives 

are slightly different. Please keep in mind when driving stakes that at least some undiscovered and/or unmarked clutches are probably present on every beach. Drive stakes 

with caution. 

I. Marking nest sites to protect buried eggs from hazardous activities

The goal of this marking method is to clearly identify the nest area and protect it 

from human activities such as beach cleaning, vehicular traffi c, or construction. Any such 

construction activity that occurs on the nesting beach during nesting season, including 

beach cleaning, must have a valid permit from the DEP (see Section 1 for additional information on construction permitting). Activities such as the placement of beach furniture 

may, at the discretion of DEP, be exempted from permitting. 
97

Figure 2-13. A loggerhead false crawl showing 

a primary body pit with an abandoned egg 

cavity (E).

Figure 2-14. A green turtle nest site on an open beach showing 

a secondary body pit (A) and a mound of thrown sand (B) that 

is greater than twice as long as the visible secondary body pit. 

Note that smaller nest mounds are expected when obstacles or 

vegetation impede digging.

Figure 2-15. A green turtle false crawl on an open beach showing 

an abandoned primary body pit (C) and a mound of thrown 

sand (D) that is smaller than twice as long as the visible primary 

body pit. Note that many green turtle nests may have body pits 

and nest mounds that look similar to this.
98

If at all possible, visually inspect the site to determine whether a nest exists. 

We do not recommend that nests be dug into simply to verify the presence of eggs. If 

you are not sure whether eggs were deposited, be conservative and mark the area as a 

nest. The entire disturbed area (where digging has occurred) should be delineated with 

stakes (Figure 2-16). Construction permits generally require that the nest site be marked 

with a radius of at least three feet, centered at the approximated location of the clutch. 

The stakes should extend about 36” above the sand. To further identify the nest site, 

surveyor’s ribbon can be tied from the top of one stake to another to create a perimeter 

around the nest site. Additionally, a nest sign can be attached to one of the stakes used 

to create the perimeter (signs are available from FWC—see Appendix C). A nest-identifying number and the date the eggs were laid should be placed on at least one of the nest 

perimeter stakes. At least one additional stake should be placed a measured distance 

from the clutch location at the base of the dune or seawall to ensure that a future location of the nest is possible should the nest perimeter stakes be lost.

II. Marking nest sites to determine hatching success

The goal of this marking method is to allow an investigator to locate the clutch in 

order to evaluate the hatching success of a nest. Nests should be marked by locating the 

precise location of the clutch at a fresh nest site by carefully digging shallow, fi nger probing holes into the nest, by fi nger-probing for softer sand over the clutch, and by verifying 

the location of the eggs. Digging into a nest may alter the incubation environment if not 

done carefully and with lengthy training. It is preferable to avoid digging into a nest site 

unless the nest will be screened, caged, relocated, or marked for hatching success.

To locate the clutch in a fresh nest, note the characteristics 

of the nest site to predict the location of the clutch. To approximate 

the location of a loggerhead clutch, follow the tracks emerging from 

the water and leading towards the nest site. Commonly, the clutch 

is located about two feet into the broad disturbed area (the nest 

mound) from this approach; it is generally centered between the 

edges of this area. To estimate the location of a green turtle clutch, 

measure about three feet back from the escarpment created by the 

fi nal covering activities. On leatherback nests, measure about 4.5 

feet from the escarpment created by the fi nal covering activities.

To precisely locate the clutch within the approximated area, dig gently and 

systematically by hand into the nest site. Focus the digging effort at the center of the 

mound of sand that was piled by the nesting turtle. Probe with fi ngers only, feeling for 

the softer (less compact) sand that will be on top of the clutch. Do not use shovels or any 

other tools. Once the soft sand is found, and the eggs beneath are verifi ed, fi ll the hole 

with moist sand and gently pat the sand surface above the eggs with your hand. Replace 

the dry sand over this area to the depth present before you began, and place a temporary 

Figure 2-16. 

Entire disturbed area of 

nest site marked.

Figure 2-17. Approximate 

location of egg chamber in a 

typical loggerhead nest.

egg chamber
99

marker over the clutch site. Rebury any other holes dug in the nest site so that the nest 

site is restored to its original condition.

To mark the nest site, measure the exact distance from the precise or approximate clutch location to two separate marking stakes on the dune that are aligned so that 

a straight line between them orients directly toward the location of the clutch (Figure 

2-18). If the clutch location is approximate, note the distance between the approximate 

clutch location and the edges of the disturbed area in each of four opposite directions. 

Both stakes should be labeled with an identifying nest number and the date the eggs 

were laid. On beaches where removal of marking stakes by the public is a potential 

problem, an additional stake, driven deeply and hidden from view, should be placed a 

measured distance landward of the fi rst two. As added insurance, an aluminum marker 

can be buried hand-deep and 24” from the approximate clutch location in a standardized 

direction. This metal marker can be found later with a metal detector.

Use the marking stakes to fi nd the egg chamber. Many times, a clutch may not 

produce hatchlings and the location of the clutch will not be indicated by the conspicuous signs of hatchling emergence. Moreover, some hatchling emergence evidence 

near the nest site may be from a nest other than the one that was marked for hatching 

success. To accurately determine overall hatching success, it is very important that the 

clutches from all marked nests be found and evaluated. A nest from which hatchlings did 

not emerge will be more diffi cult to locate again, but an inability to fi nd these nests, and 

their exclusion from the sample representing one’s beach, will result in overestimating 

hatching success for the beach. Please make the greatest effort possible to locate all nest 

cavities after waiting the appropriate length of time.

HATCHING SUCCESS EVALUATIONS (NEST INVENTORIES)

Hatching success must be determined for all caged, screened, and relocated 

nests. Hatching success may also be conducted on all other nests or on a sample of nests 

on the beach. A hatching success evaluation involves the excavation and inventory of 

a post-emergent nest to determine the fate of each egg. Because sea turtle eggs are 

subjected to a variety of incubation environments, including many that are affected by 

human activities, we encourage you to conduct nest inventories for hatching success on 

a representative sample of the nests in your survey area each year.

Selecting Nests To Be Marked for Inventory

A proper, representative sample of nests will allow assessments of hatching success that can be compared to other beaches and to other nesting seasons. To properly 

represent the beach, nests in a marked sample must be chosen by a system that removes 

seasonal, spatial, and observer bias. A sample of nests that is not properly representative can over- or under-represent certain zones on the beach or certain portions of the 

Figure 2-18. Site A stakes are 

directly landward of the nest in 

dune vegetation or at the base 

of a seawall. Site B stakes are in 

a similar position as Site A but 

located at an angle from the 

nest. Stakes A-1 and B-1 should 

be sunk deeply so that they are 

not conspicuous to someone 

not looking for them. Precisely 

measure the distance from stakes 

to the clutch location. Then, sink 

additional stakes (A-2 and B-2) 

directly between the clutch and the 

dune stake(s).
100

season. For example, a sampling strategy whereby a set number of nests are marked 

each day will always under-represent the middle of the nesting season. A sample of nests 

that is poorly representative, no matter how numerous, will yield potentially misleading 

information about hatching success.

Like selecting a representative sample of nests, it is also important to use (monitor and inventory) nearly every nest in the sample. Because the most diffi cult-to-fi nd 

nests often have the poorest hatching success, the more these nests are excluded from 

a sample, the more the sample paints a rosier picture of hatching success than actually 

exists. Before giving up on fi nding a sample nest, one should feel confi dent that they 

know the fate of the nest and that failure to fi nd it is due to its destruction (e.g., from erosion) and not due to imperfections in nest-marking techniques (e.g., stakes washing away 

from a surviving nest).

The best way to select a representative sample of nests is to decide in advance 

which nests of the season will be in the sample. If all nests on the beach can be marked 

and inventoried, then this selection is simple; mark and inventory all nests (but be sure 

not to overestimate how many nests can be sampled; marking nests is easy, inventorying 

them is diffi cult). However, if only part of the nests on a beach can be sampled, then every 

nth nest should be marked as a sample nest. With this technique, “n” is a number that sets 

a pace for nest marking that results in a sample size that is adequate, but not too large to 

handle. Here are some examples of how to use this technique:

On beach A, surveyors feel they can mark, monitor, and inventory about 100 

nests. In an average season, this beach gets about 2000 nests. Here, marking every 20th 

nest will reach the goal if the season is average. Note that the 20th nest is independent 

of the date of the season. For example, if on the fi rst day of the season there are 19 nests, 

the fi rst marked sample nest will be the fi rst nest encountered (nest number 20) on the 

second day of the season. The second sample nest will be the 40th nest, the third will be 

the 60th ... etc.

Using a subtle modifi cation to the above technique, some surveyors may wish to 

mark sample nests only one day per week. This is fi ne. To adjust the sampling protocol, 

divide your “n” by 7 to determine what nests to mark on the one day per week when 

nest-marking is done. For example, if your calculations are that every 35th nest at your 

beach needs to be marked in order to keep a pace that would result in 100 nests marked, 

then every 5th nest marked one day-per-week would keep the same pace and give an 

adequate sampling of nests. This math gets only slightly more diffi cult if the “n” for the 

beach is not divisible by 7. For instance, if 2500 nests are expected, and 100 sample 

nests are needed, (which gives a daily pace of marking every 25th nest) then the pace for 

marking nests one day-per-week would be 25 divided by 7, or every 3.6th nest. Of course, 

there are no fractional nests. In this case one can approximate a pace to achieve 100 

nests by choosing two alternating n’s that bracket the number calculated. In this case, 3 

and 4 bracket 3.6, and a proper pace would be to mark the 3rd, then 7th, then 10th, then 
101

14th nests ... etc. FWC staff can help with any questions on proper 

sampling of nests for hatching success.

Marked nests should be monitored on a regular basis, 

preferably each morning during the incubation period. Predation 

to the nest and other signifi cant events should be noted. It is 

important to give marked sample nests the same treatment as 

other nests. Do not relocate, screen, or cage a nest just because it is 

a sample nest. During sample-nest monitoring, treat sample nests 

like other nests, that is, “clean up” depredated sample nests only if 

this practice is carried out for all other nests.

Nest Inventory

To conduct a nest inventory, begin by excavating the 

nest. Carefully dig down into the nest chamber with your hands 

until you reach eggs or eggshells. D o not use shovels or other 

tools. If you encounter live hatchlings before reaching any eggs 

or eggshells, the hatchlings have probably not fi nished emerging. 

Quickly cover the egg chamber with moist sand and return the site 

to its original condition. Wait at least 24 hours before excavating 

again.

Carefully remove the contents of the nest and place them 

in a pile on the sand or in a tray for easier sorting (Figure 2-19). 

Separate the contents into the following categories: hatched 

eggs (empty eggshells), live hatchlings, dead hatchlings, pipped 

eggs with live hatchlings, pipped eggs with dead hatchlings, 

and unhatched eggs (Figure 2-20). In pipped eggs, the turtle has 

broken through the egg but the hatchling is not completely free of 

its eggshell. Pipped eggs range from those with just a small hole 

to those with large tears. 

Determine and record the number of eggs that hatched by 

carefully counting the eggshells (Table 2-1). Count each eggshell 

that is more than 50% complete as one hatched egg and disregard 

the smaller pieces. Be sure that all the eggshells are completely 

separated from each other. Record the number of live and dead 

hatchlings. These will account for some of the hatched eggs. The 

rest of the hatched eggs represent hatchlings that emerged from 

the nest. To determine the number of hatchlings that emerged 

from the nest, subtract the sum of live and dead hatchlings from 

the total number of hatched eggs. The sum of the live, dead, and 

emerged hatchlings should equal the number of hatched eggs.

Figure 2-19. Removal of nest 

contents.
102

Hatched eggs

Unhatched eggs

Pipped egg with dead 

hatchling

Partially developed embryo

Egg with no discernible 

embryo

Figure 2-20. Categories of the 

contents of a nest.

Table 2-1. Contents of a Post-Emergent Nest

Hatched eggs = 98

Live in nest = 3

Dead in nest = 1

Live pipped = 0

Dead pipped = 1

Unhatched eggs = 5

No discernable embryo = 3

Partially developed embryo = 1

Fully developed embryo = 1

TOTAL # EGGS = 104

Next, determine and separately record the number of pipped eggs with live 

hatchlings, the number of pipped eggs with dead hatchlings, and the number of 

unhatched eggs. Finally, determine the number of eggs originally present in the nest 

by adding together the hatched eggs, the pipped eggs, and the unhatched eggs. After 

completing the nest inventory, the nest contents can be reburied within the original egg 

chamber.

A nest inventory may only be conducted either 72 hours after the fi rst sign 

of emergence or 70 days after the eggs were deposited (80 days for leatherbacks), 

whichever occurs fi rst. Digging into a nest before some hatchlings have emerged may 

adversely affect these hatchlings. Because cooler temperatures sometimes delay hatching and emergence, a nest that has been subjected to inundation, excessive rainfall, 

shading, or cool fronts, should not be excavated until 80 days after egg deposition or 96 

hours after the fi rst emergence. It is important to allow all hatchlings to emerge naturally 

before excavating the nest.

Note: If the fi rst emergence of a nest has occurred (more than 3 hatchling tracks) 

and the hatchling tracks indicate a clear sign of disorientation you should contact the 

property owner responsible for the offending light(s), explain the situation, and ask 

them to turn the light(s) off. If the property owner cannot be reached or is not receptive 

to turning off the light(s) you may place a temporary restraining cage over the nest to 

contain the next emergence of hatchlings...
103

For the subsampling technique to succeed, a sampling plan based on the total 

number of nests expected has to be devised before the nesting season so that the 

sample of nests marked for evaluation will represent hatching success over the entire 

nesting season and nesting beach. The easiest way to do this is to mark for evaluation all 

nests made every other day, or every three days, or every fi ve days, etc. (for a statistically 

valid sample, you should try to mark and evaluate at least 100 nests). Once a sampling 

plan is initiated, it should be followed throughout the nesting season. FWC sea turtle 

program staff are available to assist you in developing the best approach for your particular survey area. 

When a nest marked for evaluation is completely depredated (all the eggs are 

destroyed), record this (no further evaluation is necessary). This nest is a very important 

part of your sample to accurately determine overall hatching success. Do not select 

another nest as a replacement. When a nest marked for evaluation is partially depredated, remove and count the depredated eggs. Cover the egg chamber with moist sand, 

and return the site to its original condition. Record the nest as partially depredated and 

record the number of eggs that were depredated. Then, at the appropriate time, inventory the remainder of the nest.

During nest inventories, some live hatchlings or pipped eggs with live hatchlings may be encountered. If this happens often, try waiting a day or two longer before 

conducting the inventory. Pipped eggs with live hatchlings or live hatchlings that have 

prominent yolk sacs may be carefully re-buried at the top of the egg chamber or held on 

moist sand (not in water) until ready for release. If pipped eggs or hatchlings are held on 

moist sand, they are to be kept in a darkened, quiet, temperature-controlled area. When 

ready, these hatchlings are to be released on the beach at night and allowed to crawl to 

the water. See the following section for more information on the rescue and release of 

live hatchlings.

HATCHLING RESCUE AND RELEASE

This activity includes salvaging live hatchlings (primarily disoriented hatchlings 

or those found at the bottom of excavated nests) and ensuring that they reach the water 

safely. Hatchling rescue and release does not authorize permit holders to conduct public 

hatchling releases. See Section 7-4 for information on conducting public hatchling 

releases.

Due to the short duration of the hatchling frenzy period, hatchlings should be 

released as soon as possible following rescue. All hatchlings found during darkness are 

to be released immediately. Small numbers of hatchlings (<5) that are found disoriented 

or at the bottom of nests during daylight excavation may also be released on the beach 

immediately (but no later than 9 am). Otherwise, rescued hatchlings must be released 

the following night. Hatchlings collected from excavated nests should never be held in 
104

water. Small Styrofoam or plastic coolers lined with damp sand work well as temporary 

holding containers. The lid of the cooler should be placed loosely over the top to provide 

a near-dark environment. Once placed in a holding container, hatchlings should not be 

handled or disturbed until they are ready for release. Activity causes increased expenditure of limited energy stores.

Hatchlings should be placed on the beach and allowed to crawl to the water on 

their own. Artifi cial lights should not be utilized during hatchling releases. This applies 

to any members of the public observing such releases, as well as all permitted personnel 

involved in the release. A quick check of the release area with a small fl ashlight a short 

time after release will insure that all hatchlings have reached the water. Occasionally, 

individual hatchlings may need assistance in reaching the water. In such cases, they may 

be moved closer to the water’s edge or placed in the shallows and allowed to swim off on 

their own.

In some cases, weak hatchlings may need to be held for slightly longer periods 

(1-2 days) to allow them to recover. However, holding hatchlings overnight should not 

be a routine event. If hatchlings require further holding, contact FWC to arrange for their 

transfer to an authorized rehabilitation facility.

HATCHLING AND ADULT DISORIENTATION

Although sea turtles do nest on beaches with artifi cial lights, there is much 

evidence suggesting that they prefer darker beaches. When sea turtles choose to nest on 

lighted beaches, their hatchlings are at great risk. In Florida, artifi cial lighting is probably 

the single greatest human threat to emergent hatchlings trying to reach the ocean. 

Both hatchlings and nesting adults exposed to artifi cial lighting can be led in the 

wrong direction (become misoriented) or meander and circle (become disoriented). It is 

extremely important that sea turtle permit holders who conduct nesting surveys look for 

and document signs of disorientation. These events should be reported on the standard 

reporting forms. Because we may be able to immediately resolve a lighting problem and 

thus avoid subsequent problems, it is very important that you inform the FWC Tequesta 

offi ce of all disorientation events as soon as possible. You can fax the forms to Tequesta 

at: (561) 743-6228.

Some indirect tracks from adult turtles may not be due to artifi cial lighting. Adult 

females in search of a nesting site may wander on the beach for a period of time looking 

for a suitable nesting site. Leatherback turtles are known to make orientation circles on 

their way back to the ocean after nesting. A diagram of the crawl should be included with 

adult disorientation reports to help assess the actions of the turtle.

Wind and rain may obscure tracks, making it diffi cult to document hatchling 

disorientation. Still, every effort should be made to count the number of hatchlings 
105

disoriented. Counting the tracks farther from the nest, in the area where the tracks 

spread out, is generally a little easier than trying to count the tracks right next to the egg 

cavity.

Identifying the light source is also important. If the disorientation was documented during a morning survey, and if time and personnel permit, a subsequent nighttime lighting survey would be useful in identifying the light source. The address of the 

property, and the number, type, and location of lights are important to the local code 

enforcement persons and/or FWC. Several counties and municipalities have lighting 

ordinances. A list of local ordinances and contact numbers can be found in Appendix 

C. In cases where a local ordinance is in place, the local code enforcement person is 

generally responsible for ensuring compliance with the ordinance. In areas where there 

is no local ordinance, FWC tries to work with the property owner to correct the problem 

light(s). Please notify the local code enforcement offi ce and/or FWC as soon as possible 

after a disorientation event.

NEST RELOCATION

Summary

This section is specifi cally intended for those persons whose permit authorizes 

them to relocate nests. These personnel are also authorized to:

· mark nests

Personnel are not authorized to conduct the following activities unless specifi -

cally stated on their permit:

· conduct nesting surveys

· protect nests with self-releasing screens/cages

· protect nests with restraining cages

· use a self-releasing hatchery

· use a restraining hatchery

· relocate a clutch at anytime after 9:00 a.m. the morning following deposition

· use probes (other than fi ngers) to locate clutches.

ACTIVITY DESCRIPTION

Moving sea turtle eggs creates many opportunities for adverse impacts. 

Movement alone is known to kill developing embryos by disrupting delicate membranes 

that attach to the inside of the egg. Because the incubation environment greatly infl uences the developing embryo, nest relocation can involve the transfer of eggs from an 
106

appropriate environment to an inappropriate one. For this reason, nest relocation is 

considered a management technique of last resort.

Natural events, like storms, that accelerate beach erosion and accretion can 

sometimes reduce hatching success in existing nests. While damage from storm events 

can be severe, it is diffi cult to predict the precise areas where the storm is most likely to 

infl ict damage. Because of the negative effects of relocating eggs and the unpredictability of storm events, FWC does not generally authorize permit holders to move nests out 

of areas threatened by storms. As a general rule, nests should only be relocated if they 

are low enough on the beach to be washed daily by tides or if they are situated in well 

documented high-risk areas that routinely experience serious erosion and egg loss (e.g., 

nests laid near river mouths or beneath eroding sea walls).

FWC does not generally authorize nest relocation for heavy foot traffi c, lighting 

problems or beach cleaning. Foot traffi c is not known to cause problems for nests, but if 

traffi c is heavy, a nest can be marked so that it will be avoided by pedestrians. If a nest is 

made near a light that may misorient the hatchlings, efforts should focus on getting the 

light turned off or shielded (if protection is necessary, the nest should be caged). If nests 

are deposited on beaches that are periodically raked with mechanical equipment, beach 

raking should be discontinued or the nests should be marked clearly so that they can be 

avoided by the beach cleaners.

When a nest does require relocation, the eggs must be moved no later than 9:00 

a.m. the morning following its deposition. About 12 hours after deposition, the potential 

for movement-induced mortality in sea turtle eggs increases rapidly. Eggs should be 

moved no later than 12 hours after deposition (turtles may nest as early as 9:00 p.m. the 

preceding night). To relocate a nest, fi nd the location of the egg chamber by gently and 

systematically digging by hand, and probing with fi ngers only. Never use shovels or any 

other tools for either digging or probing. Once the eggs are located, carefully remove 

the sand from around the top eggs. Individual eggs should be gently lifted from the egg 

chamber and placed into a rigid container with a 2”–3” layer of moist sand on the bottom. 

When moving eggs, be sure to maintain each egg’s original orientation; do not rotate 

eggs in any direction and avoid abrupt movements. As eggs are placed in the container, 

be sure that they do not roll. Eggs are to be shaded if relocated after sunrise. The easiest 

way to do this is to lay an open umbrella on its side (because there may be eggs incubating nearby, do not stick the umbrella into the ground) or place a towel over the top of the 

container holding the eggs. When all eggs are in the container, cover them with a layer of 

moist sand.

Find a suitable nearby location on the beach that is successfully used by nesting 

turtles. Be sure that the new nest site is above the high tide level but not in dense vegetation. With your hands, dig a new nest chamber to the same depth, size, and shape of 

the original nest. The shape of the nest chamber should be such that there is a spherical 

bottom and a slightly narrower neck. The depth of a loggerhead nest chamber should be 
107

18–22 inches and the diameter of the spherical bottom should be volleyball to basketball 

size. The neck should only be 2–4 inches more narrow than the bottom. Clutches that 

are greater than or less than average may require respective nest-chamber dimensions 

that are larger or smaller. Place the eggs in the new egg chamber by transferring them 

one at a time while continuing to maintain each egg’s original orientation. After all the 

eggs have been transferred into the new egg chamber, cover them with the moist sand 

excavated from the egg chamber. Dry sand should not be allowed to fall into the egg 

chamber. Once the eggs are reburied to the upper level of the surrounding moist sand, 

gently pat the sand surface above the eggs with your hand. Replace the dry sand over 

this area to the depth present before you began. The relocated nest can then be marked 

and later evaluated for hatching success.

SPECIAL PERMIT CONDITIONS FOR USING HATCHERIES

Because the use of hatcheries requires that eggs be relocated, it is not considered 

a preferred management technique (see FWC’s Sea Turtle Conservation Guidelines, 

Section 2, Nest Relocation). However, the use of hatcheries is authorized by FWC in a 

limited number of areas where artifi cial lighting problems are extreme. These areas typically have little or no sections of beach where nests can be left in-situ without emerging 

hatchlings becoming disoriented by artifi cial lights. Persons authorized to relocate nests 

to a hatchery must follow the guidelines for Nest Relocation in Section 2 of the Sea Turtle 

Conservation Guidelines. Nest success evaluations are required for ALL nests relocated to 

self-releasing or restraining hatcheries.

Self-releasing hatcheries are typically located on dark areas of beach. Nests 

placed in a self-releasing hatchery should be spaced uniformly at least one meter apart 

and marked using a stake(s). The purpose of marking nests in a self-releasing hatchery 

is to ensure that previously relocated nests are not inadvertently dug up or placed too 

close to each other. Stakes are also needed later to evaluate nest success. Nests in selfreleasing hatcheries must be checked daily by permitted personnel [to monitor threats 

to the nests].

Restraining hatcheries are utilized in areas where there are no sections of the 

beach dark enough to allow hatchlings to emerge and fi nd the water on their own. 

Restraining hatcheries must be checked for emerging hatchlings at least three times a 

night (once between 9 p.m. and 11:00 p.m., once between 12:00 a.m. and 2:00 a.m. and 

once between 3 a.m. and 5:00 a.m.) beginning 45 days after the fi rst clutch is deposited in 

the hatchery and ending when all nests in the hatchery have emerged. Release locations should be varied to avoid creating a feeding station for in-water predators. During 

the day, the hatchery must be checked at least once every half hour unless the seaward 

side of the hatchery can be opened in such a way that hatchlings emerging during the 

daytime can escape the hatchery and crawl to the ocean on their own.
108

Hatcheries must be situated in areas that mimic good-quality sea turtle nesting 

habitat. If located on the seaward side of a primary dune the hatchery should be at least 

one-meter vertical distance above the level of the highest spring tides to prevent excessive inundation of the eggs. Hatcheries should be located in areas exposed to the sun 

most of the day and where vandalism is not a concern. Hatcheries should not be situated 

near drainage or outfall pipes. Hatcheries must be in good physical repair and maintained in such a way that vegetation does not encroach into the hatchery. To prevent 

infestation from fungus and bacteria, the sand in the hatchery must be replaced every 

year prior to the beginning of the nesting season to a minimum depth of three feet.

Hatcheries may not be used to store any type of equipment other than nest 

marking materials (i.e., stakes, bottomless buckets, etc.). Under no circumstances may 

hatcheries be used to store vehicles (e.g., ATV’s), gasoline, or other equipment that may 

be potentially harmful to incubating nests or that pose an entanglement risk to emerging 

hatchlings.
109

Appendix C: Sea Turtle Stranding and Salvage Network 

(STSSN) Coordinators

Barbara Schroeder, National Sea Turtle Coordinator,

NOAA/National Marine Fisheries Service 6/6/03

National Coordinator

Wendy Teas

National Marine Fisheries Service

Southeast Fisheries Science Center

75 Virginia Beach Drive

Miami, FL 33149

(305) 361-4595

(305) 361-4478 fax

wendy.teas@noaa.gov

State Coordinators

Texas

Dr. Donna Shaver

U.S. Geological Survey

Padre Island National Seashore

P.O. Box 181300

9450 S. Padre Island Drive.

Corpus Christi, TX 78480-1300

(361) 949-8173 ext. 226

(361) 949-1312 fax

Donna_Shaver@usgs.gov

Louisiana

Contract surveyor for western Louisiana 

(There is currently no state coordinator.):

Dr. Gregory Hartman

McNeese State University

Department of Biological & Environmental Sciences

P.O. Box 92000

Lake Charles, LA 70609

(337) 475-5672

(337) 475-5677 fax

ghartman@mail.mcneese.edu

Mississippi

Gary Hopkins

U.S. Department of the Interior

National Parks Service

Gulf Islands National Seashore

3500 Park Road

Ocean Springs, MS 39564

(228) 875-9057 ext 104

(228) 872-2954 fax

gary_hopkins@nps.gov

Alabama

Celeste South

U.S. Fish and Wildlife Service

Ecological Services Field Office

1208-B Main Street

Daphne, AL 36526

(251) 441-5181

Celeste_South@fws.gov
110

Florida

Dr. Allen Foley

Florida Fish and Wildlife Conservation Commission

Florida Marine Research Institute

Jacksonville Field Laboratory

6134 Authority Avenue, Building 200

Jacksonville, Florida 32221

(904) 573-3930

(904) 573-4982 fax

allen.foley@fwc.state.fl.us

Georgia

Mark Dodd

Georgia Department of Natural Resources

Marine Resources Division

1 Conservation Way

Brunswick, GA 31520

(912) 280-6892

(912) 262-3143 fax

mark_dodd@dnr.state.ga.us

South Carolina

Sally Murphy

South Carolina Department of Natural Resources

Box 12559

217 Ft. Johnson Rd.

Charleston, SC 29422-2559

(843) 953-9014

(843) 953-9353 fax

murphys@mrd.dnr.state.sc.us

North Carolina

Matthew Godfrey 

Sea Turtle Program Coordinator 

North Carolina Wildlife Resources Commission 

307 Live Oak Street 

Beaufort, NC 28516

(252) 728-1528 

godfreym@coastalnet.com

Virginia

Dr. Jack Musick

Virginia Institute of Marine Science

College of William & Mary

Gloucester Point, VA 23062

(804) 684-7317

(804) 684-7327 fax 

jmusick@vims.edu

Mark Swingle

Virginia Marine Science Museum

VMSM Foundation Stranding Program 

717 General Booth Blvd.

Virginia Beach, VA 23451 

(757) 437-6022 or (757) 437-6159

mswingle@vbgov.com

Maryland

Tricia Kimmel

Maryland Department of Natural Resources

Cooperative Oxford Lab

904 South Morris Street

Oxford, MD 21654

(410) 226-5901

(410) 226-0120 fax

tkimmel@dnr.state.md.us

Delaware

Suzanne Thurman

MERR Institute, Inc.

P.O. Box 411

Nassau, DE 19969

(302) 228-5029

(302) 684-4976 fax

merrins@earthlink.net
111

New Jersey

Robert Schoelkopf

Marine Mammal Stranding Center

P.O. Box 773

3625 Brigantine Blvd.

Brigantine, NJ 08203

(609) 266-0538

mmsc@bellatlantic.net

New York

Kimberly Durham

Riverhead Foundation for Marine Research and 

Preservation

431 East Main St.

Riverhead, NY 11901

(631) 369-9840 ext. 22

(631) 369-9826 fax

KDurhamNY@aol.com

Connecticut/Rhode Island

Heather Medic

Mystic Marinelife Aquarium

55 Coogan Blvd.

Mystic, CT 06355

(860) 572-5955 ext. 107

(860) 572-5969 fax

hmedic@mysticaquarium.org

Massachusetts (Boston South)

Robert Prescott

Massachusetts Audubon Society

Wellfleet Bay Wildlife Sanctuary

P.O. Box 236

South Wellfleet, MA 02663

(508) 349-2615

(508) 349-2632 fax

rprescott@wellfleetbay.org

Massachusetts (Boston North), New Hampshire, Maine

Connie Merigo

New England Aquarium

Rescue Rehab Program

Central Wharf

Boston, MA 02110

(617) 226-2102

cmerigo@neaq.org
U.S. Department of Commerce

National Oceanic and Atmospheric Administration

NOAA Ocean Service

Donald L. Evans

Secretary, U.S. Department of Commerce

Vice Admiral Conrad C. Lautenbacher, Jr., USN (Ret.)

Under Secretary for Oceans and Atmosphere and NOAA Administrator

Richard W. Spinrad, Ph.D.

Assistant Administrator

Ocean Services and Coastal Zone Management

August 2003